Reviews You Can Rely On

The 5 Best Ultralight Sleeping Bags of 2023

We get moving fast and light with ultralight sleeping bags from Feathered Friends, ZPacks, Western Mountaineering, and more to find the best option for you
Best Ultralight Sleeping Bag of 2023
Comparing and testing mummy bags in the Bighorn Mountains of Wyoming, we found that the Vireo had by far the most spacious fit through the torso, and was also really light!
Wednesday December 21, 2022
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Over the last ten years, we have bought and tested over 42 ultralight sleeping bags. This review compares 18 of the best models. Our expert gear team of rock climbers, thru-hikers, and fast packers spent countless nights sleeping in these bags across the globe. From frigid mountain summits to low desert canyons, these bags have been carried for miles and miles in different environments. We also put them through controlled temperature testing. Whether this is your first foray into the ultralight world or you are an old hat looking to update your gear, we're here to help you find the perfect bag for your ultralight adventures.

If you're an ultralight enthusiast, we've got your back (literally — we can save you from carrying extra weight!) Check out our sleeping pad review to find the most comfortable lightweight model and our picks for the best ultralight tents and backpacking tents for a lightweight shelter to carry on the trail. We've also tested a ton of other backpacking gear to get you out the door and on your way.

Editor's Note: We updated this review on December 21, 2022, to add two new models, the Outdoor Vitals StormLoft Down TopQuilt and the Big Agnes Fussell UL Quilt. In addition, we added three of the lightest models from our Backpacking Sleeping Bag Review to the rating table to give additional comparison opportunities.

Top 18 Product Ratings

Displaying 1 - 5 of 18
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Awards Editors' Choice Award Editors' Choice Award  Best Buy Award Top Pick Award 
Price $469 List
$469.00 at Feathered Friends
$450.00 at Backcountry
Compare at 2 sellers
$409 List$320 List$549 List
$549.00 at Feathered Friends
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Pros Highest scoring ultralight sleeping bag, best features, and most versatileWarmth-to-weight ratio, excellent fabric, best bag with a hood, versatileWarm for an ultralight bag, simple and versatile design, box baffle construction, waterproof stuff sackVery affordable, highly customizable, versatile, lots of featuresSuper lightweight, incredible loft, snag-proof zipper, cozy hood
Cons Not as warm as others (in the version we tested), neck draw cords loosen over timeTight fit, shallow hood, expensiveA little constricting, small foot box, not the best neck draw cord designLong wait for product to be custom made and shipped, foot box draw cord still leaves a little hole, lots of buttons and strapsUncomfortably narrow dimensions, bare-bones design, noisy fabric
Bottom Line The highest scorer because of its versatile design that allows it to be a fully opened blanket or a fully zipped hoodless mummyA stellar choice for those looking for a warm, lightweight, fully hooded mummyA top-scoring bag that's warm and versatile enough for full three-season use, while weighing impressively littleOffers the versatility of sleeping under it as a blanket or fully wrapped up, with a huge range of customizable optionsOur favorite when ounces matter, this is a full-size mummy bag that's both warm and ultralight
Rating Categories Feathered Friends F... Western Mountaineer... ZPacks Classic Enlightened Equipme... Feathered Friends H...
Warmth (30%)
Weight (25%)
Comfort (20%)
Versatility (15%)
Features (10%)
Specs Feathered Friends F... Western Mountaineer... ZPacks Classic Enlightened Equipme... Feathered Friends H...
Manufacturer Stated Temperature Rating 40F 32F 20F 20F 30F
Measured weight, bag only (ounces) 19.1 oz 19.0 oz 20.3 oz 20.9 oz 23.2 oz (size Long)
Stuffed Size 7" x 10" 6" x 12" 6" x 12" 7" x 12" 7" x 10"
Stuff Sack Weight 0.8 oz 1.0 oz 0.9 oz 0.6 oz 0.8 oz
Manufacturer Claimed Weight 20.0 oz 19.0 oz 19.8 oz 20.2 oz 21.3 oz (size Regular)
Fill Weight 8.4 oz 10.0 oz 13.1 oz 13.0 oz 12.0 oz
Shell Material Pertex Endurance UL 100% nylon ripstop 0.70 oz/sqyd (23.7 g/m2) Ventum Ripstop Nylon w/ DWR 10D nylon fabric 10D Pertex Endurance
Fill Power 950+ goose down 850+ goose down 900 fill 850 Downtek 950+ FP Down
Style Center zip mummy bag or unzip for quilt Hooded mummy Hoodless mummy Quilt Hooded mummy
Construction Continuous baffles Continuous baffle Vertical upper baffles and horizontal lower baffles, box baffle construction U-shaped baffled quilt Continuous horizontal baffles
Shoulder Girth 62" 59" 61" 55" 58"
Hip Girth 48" 51" 61" 55" 52"
Foot Girth 39" 38" 35" 55" 38"
Zipper Length Full-length center zip Full-length 3/4-length 1/3-length at bottom Full-length side zip
Sizes Regular, long, and wide 5'6", 6', and 6'6" Slim, standard, and broad (girth) short, medium, long, x-long and xx-long (length) Short/regular, regular/regular, regular/wide/ long/wide Regular, long
Temp Options (degrees Fahrenheit) 20, 30, 40F 32F 10, 20, 30, 40F 10, 20, 30, 40F 20, 30F

Best Overall

Feathered Friends Flicker 40 UL

  • Warmth 7.0
  • Weight 5.0
  • Comfort 7.0
  • Versatility 10.0
  • Features 10.0
Weight: 19.1 oz | Fill: 950+FP Goose Down
Super high fill power down
Functions as a quilt or a mummy bag
Full-length zipper with baffle gives you complete enclosure
No hood
Not quite as light as the lightest bags available

Due largely to its incredible versatility, the Feathered Friends Flicker 40 UL wins top honors yet again in our review. Whether trying to ventilate on a hot night or bundle up when the mercury drops, this bag has you covered. A full-length zipper down the center allows it to be used as a hoodless mummy bag or a flat quilt, giving you two great sleeping options. The Flicker 40 pairs super high loft, 950+ fill power down with a shell made of water-resistant and breathable Pertex Endurance UL. Feathered Friends spared no expense and used only the best and lightest materials in this masterpiece.

This is not the warmest bag--we opted to test the 40F version to try out the lightest Flicker available, and it kept us warm in that temperature range, but any colder, and we weren't exactly toasty. Check out the 30F and 20F options if you want extra warmth for a bit more weight. The lack of a hood also reduces the warmth on cooler evenings. We like the dual drawcords at both the head and feet, which lets you wear it around camp on chilly mornings, and the full-length zipper is far higher quality and more functional than the weight-saving buckle and strap systems used on some competing quilts. The Flicker is the clear winner of this comparative review, and we recommend you start your search for an ultralight sleeping bag by checking out this model.

Read more: Feathered Friends Flicker 40 UL review

The Best Ultralight Hooded Mummy Bag

Western Mountaineering Summerlite

  • Warmth 9.0
  • Weight 5.0
  • Comfort 6.0
  • Versatility 8.0
  • Features 7.0
Weight: 19 oz | Fill: 850 Fill-Power Down
A fully enclosed mummy bag with hood
Warm and thermally efficient
Lightweight for a full-zip hooded mummy
Tight cut
Shallow hood

When something works well, we don't see a good reason to change it. For many good reasons, the Western Mountaineering Summerlite has been around a while and is a stalwart ultralight bag. Although it isn't EN rated, it seems appropriately warm for its 32F rating bolstering our belief that Western Mountaineering's approach to temperature ratings tends to be much more conservative than others. The Summerlite sandwiches high-quality 850 fill-power down between 12-denier fabric coated in a robust DWR to make a toasty package for a good night's sleep. Despite the full-length zipper and hood, the Summerlite comes in at a competitive weight of 19 ounces. It's a versatile bag and light or lighter than most of the quilt models we tested.

The one sacrifice it does make is a tighter cut, especially at the legs, so this may not be a great choice for larger folks or more restless sleepers. But because it's a regular mummy, it's less dependent on matching with a specific pad, so it can be used whether you're stretching out in a hut along the Appalachian Trail or curled up on a frozen sloping ledge on the side of a mountain. The Summerlite is our favorite full mummy bag for ultralight users, despite its tighter shape.

Read more: Western Mountaineering Summerlite review

Quilts vs. Mummy Bags
We know that quilts versus mummy bags can be a polarizing topic. There are excellent arguments on both sides of this issue; therefore, we chose a favorite bag for each type. Some of our testers prefer quilts, and some prefer mummies, and that's just fine. We set out on this review to provide info to both schools of thought. Our only firm conclusion is that your needs supersede anyone else's opinion.

Best Bang for the Buck

Enlightened Equipment Revelation 20

  • Warmth 9.0
  • Weight 4.0
  • Comfort 6.0
  • Versatility 8.0
  • Features 8.0
Weight: 20.9 oz | Fill: 850 Fill-Power Down
Great value
Warm for a quilt
Lofty 850 fill power, hydrophobic down
Lots of customizable options
Constrictive when fully buckled up
Long, dangly drawcords

For many people, the weight-to-warmth ratio isn't the only consideration for ultralight gear. Price is also important. The best balance is the Enlightened Equipment Revelation 20. It didn't score quite as high as the Feathered Friends Flicker, but it's available for a good amount less, with the added benefit of free shipping in the USA. It's hard to find a bag as versatile and warm as this one. The quilt can be opened into a blanket for summer nights or sealed down around a sleeping pad for maximum warmth on chilly ones. The Revelation is customizable in about every way, from fill power, fabric weight, overall width and length, and even colors. We tested the "stock" model for this review — beware that a customized quilt can take 2-4 weeks for delivery, but with a plethora of options, you can dial this one in to meet your specific desires.

If you're close to the limits of the quilt's dimensions, we recommend sizing up, as our larger testers found the quilt a bit constricting when entirely closed up. The attachment system, while very adjustable, is dangly, which is slightly annoying sometimes. However, the current model is the warmest quilt we tested and is comfortable across a wide range of temperatures, causing it to score high on our charts. For a great quilt with a justified price, the Revelation is a worthy contender.

Read more: Enlightened Equipment Revelation 20 review

Best for a Tight Budget

Hammock Gear Economy Burrow 20

  • Warmth 6.0
  • Weight 2.0
  • Comfort 7.0
  • Versatility 8.0
  • Features 8.0
Weight: 25 ounces | Fill: 800 Fill-Power Duck Down
Bargain for what you get
Decent versatility
Not that warm
Doesn't cinch as well as some

For some ultralight backpackers, shelling out extra cash for weight savings can be worth it. However, the Econ line from Hammock Gear proves that you don't need to break the bank for a quality lightweight quilt. We tested the Hammock Gear Economy Burrow 20, and we were surprised at how well it performed despite having a price that was less than half the cost of some of the premium models. It's got as many features as some of the more expensive options and isn't that much heavier.

We tested the Economy Burrow in the backcountries of Zion and Joshua Tree National Parks, and it kept us warm on nights near freezing with the added benefit of packing down surprisingly well, too. It isn't the lightest or the warmest option out there, but the price is unbeatable for a quilt as functional as this one. The size, temperature, fill, and foot box style can all be customized, which will affect the price, but it should stay under the cost of nearly every other competitive option. For bargain shoppers, this is your bag.

Read more: Hammock Gear Economy Burrow 20 review

Best for Insane Packability

Sea to Summit Spark SpI 40

  • Warmth 5.0
  • Weight 9.0
  • Comfort 6.0
  • Versatility 5.0
  • Features 6.0
Weight: 12.4 oz | Fill: 850+ Fill-Power Down
Extremely light for a mummy bag
Packs down to the size of a large grapefruit
Excellent zipper
Only appropriate for summer temperatures
Somewhat tight cut

Some go light, and some go ultralight. The Sea to Summit Spark SpI 40 is for those in the latter category. At a mere 12.4 ounces, this thing is so light and small you might lose it in your pack. The Spark comes with a compression sack that shrinks it to roughly one liter of space - the size of a Nalgene water bottle. We took this backpacking on a late summer overnight trip in southern Utah and easily fit everything into a 20-liter daypack. If careful, you can get away with carrying this inside an ultra-running vest for some fast and light mountain running adventures.

The folks over at Sea to Summit made this tiny package possible by stripping nearly everything off this hooded mummy bag. There's no draft collar or tube, only a half zipper. The baffles are sewn through the shell fabric, which harms thermal efficiency. It's not the warmest bag, but warmer than at least two quilts we tested. For seriously light summer missions, it's one cool piece of gear.

Read more: Sea to Summit Spark SpI 40 review

Compare Products

select up to 5 products to compare
Score Product Price
Feathered Friends Flicker 40 UL
feathered friends flicker 40 ul ultralight sleeping bag review
Editors' Choice Award
Western Mountaineering Summerlite
western mountaineering summerlite ultralight sleeping bag review
Editors' Choice Award
ZPacks Classic
zpacks classic ultralight sleeping bag review
Enlightened Equipment Revelation 20
enlightened equipment revelation 20 ultralight sleeping bag review
Best Buy Award
Feathered Friends Hummingbird UL 30
feathered friends hummingbird ul 30 backpacking sleeping bag review
Top Pick Award
Feathered Friends Vireo UL
feathered friends vireo ul ultralight sleeping bag review
Therm-a-Rest Vesper 32
therm-a-rest vesper 32 ultralight sleeping bag review
Western Mountaineering Astralite
western mountaineering astralite ultralight sleeping bag review
Sea to Summit Spark SpI 40
sea to summit spark spi 40 ultralight sleeping bag review
Top Pick Award
Katabatic Gear Palisade 30
katabatic gear palisade 30 ultralight sleeping bag review
Sierra Designs Cloud 800 / 35
sierra designs cloud 800 / 35 ultralight sleeping bag review
Outdoor Vitals StormLoft Down TopQuilt
outdoor vitals stormloft down topquilt ultralight sleeping bag review
REI Co-op Magma Trail Quilt 30
rei co-op magma trail quilt 30 ultralight sleeping bag review
Hammock Gear Economy Burrow 20
hammock gear economy burrow 20 ultralight sleeping bag review
Best Buy Award
REI Co-op Magma 30
rei co-op magma 30 backpacking sleeping bag review
Western Mountaineering HighLite
western mountaineering highlite ultralight sleeping bag review
Therm-a-Rest Hyperion 32
therm-a-rest hyperion 32 backpacking sleeping bag review
Big Agnes Fussell UL Quilt
big agnes fussell ul quilt ultralight sleeping bag review

ultralight sleeping bag - a solo campsite up in a side valley of the khumbu, the famous part...
A solo campsite up in a side valley of the Khumbu, the famous part of the Himalaya that is home to Mt. Everest. The 20 Degree by ZPacks kept us nice and warm on what proved to be a chilly night.

Why You Should Trust Us

The only way to test a product's performance is by using it. With this in mind, we tested these bags by sleeping in them — a lot. We used them on windy desert nights, blizzards at 15,000 feet, and everything in between. These bags have been all over the Rockies of Colorado and Wyoming, the deserts of southern Utah, and the high peaks and passes of the Khumbu, Makalu, and Manaslu regions of the Nepal Himalayas. Many people took turns sleeping in each bag, spending both cozy and miserable nights in the wilderness, suffering through enough sweating and shivering to truly understand the meaning of "temperature ratings." One of our testers even caught two colds that he blames on sleepless nights spent in these bags searching for their hidden flaws. We went the extra mile to be sure we know what we're talking about, and we hope you find this review useful.

Our ultralight sleeping bag testing is divided into five rating metrics:
  • Warmth (30% of total score weighting)
  • Weight (25% weighting)
  • Comfort (20% weighting)
  • Versatility (15% weighting)
  • Features (10% weighting)

We assembled an all-star crew to put these ultralight sleeping bags to the test, including Andy Wellman, Ethan Newman, Justin Simoni, and Jack Cramer. Andy has published guidebooks, hiked long distances in the Rockies, the Andes, and the Himalayas, and is no stranger to a night under the stars. Ethan has worked professionally outdoors for over a decade as a rock climbing guide, wildland firefighter, wilderness ranger, and environmental educator. Justin has explored the more exhilarating peaks and ridgelines of Colorado, finishing bold fastpack routes on his unsupported multi-day adventures, and has assisted with guided ultralight backpacking trips in Kings Canyon NP, Rocky Mountain NP, and Gates of the Arctic NP. Finally, Jack is an accomplished climber and Yosemite Search and Rescue team member who has personally tested more than 60 different sleeping bags. Combined, they spend over 150 nights a year in a sleeping bag, from shiver bivvies on the sides of mountains to comfy nights around a campfire with friends, and we know how to get a good night's sleep outside.

A magnificent campsite, and a great place to test out the best...
A magnificent campsite, and a great place to test out the best ultralight sleeping bags and quilts. This is near the small village of Samdo on the Manaslu Circuit in Nepal, using the Palisade 30 and The North Face Superlight 15.
The Sea to Summit Spark is great for desert backpacking when the...
The Sea to Summit Spark is great for desert backpacking when the nights don't get too cold.
With the hood tightened up as it is here, this bag felt a bit too...
With the hood tightened up as it is here, this bag felt a bit too short for our head tester, who didn't find it comfortable to use with the hood pulled over his head.

Analysis and Test Results

To compare and score every quilt and bag as objectively as possible, we narrowed overall performance down to five metrics to evaluate each bag: Warmth, Weight, Comfort, Versatility, and Features. Because some of these categories are more significant than others, we weighted each metric according to its relative importance for an ideal UL sleeping bag. Keep in mind all these scores are comparative because we are only willing to speak for the products we test, not everything that exists in the entire ultralight sleeping bag market. This is why a 30-degree Fahrenheit sleeping bag might score highly in warmth; we are comparing it to other sleeping bags of similar weight, not a 0-degree winter behemoth.

While most of these bags use high-quality materials and well-executed designs, there are limits to how lightweight things can get. In the realm of ultralight sleeping bag design, sometimes one aspect of performance must be sacrificed to aid another. For example, a tighter cut may be lighter and warmer but far less comfortable. Keep this in mind as you read through this review to be sure you identify the best balance for your needs.

ultralight sleeping bag - comparing mummy bags on an extended road trip to the bighorn...
Comparing mummy bags on an extended road trip to the Bighorn Mountains in northern Wyoming.

Ultralight vs. Traditional

What does it mean for a sleeping bag to be "ultralight"? Ultralight is a set of guiding principles to minimize weight and thus maximize how far you can go and how much fun you have. However, this principle demands that every ounce counts. So if you're trying to balance warmth, weight, and comfort, you are often only able to achieve two out of three. Some bags reduce weight by using a narrower cut or utilizing lighter, less durable materials. Still, others get by with generous interpretations of the definition of warmth.

A recent ultralight trend has been in favor of quilts rather than full sleeping bags. The idea is that any down or fabric underneath your body gets compressed and loses its loft, so why not eliminate it? Other bags eliminate hoods, shorten zippers, or strategically place the down fill to maximize warmth while keeping the weight minimal. Some of these bags are also designed to be part of a sleep system, relying on an insulated pad and the warm clothing you'll already be carrying. Still, other products blur the line between sleeping bags and quilts and cherry-pick great ideas from both types of offerings.

The bags and quilts in this review range from 9 ounces to a bit under two pounds. In contrast, our "backpacking" sleeping bag category runs from about 1.25 lbs to 3.5 lbs. There is some overlap, and the differences may seem minor, but as ultralight hikers say, "ounces make pounds, and pounds make pain." If you're not sure which category is right for you, consider checking them both out before making a purchase decision.


Although we don't factor value into our performance scores, we know it's a huge part of any purchasing decision. New gear is exciting, but most of us still want to pay the minimum amount for the gear we need. This means knowing whether shelling out extra money for a fancy sleeping bag is worth it. A common example is higher quality down that reduces weight but raises the price. High fill power goose down offers the highest warmth-to-weight ratio of any commonly available insulation. Still, it is much more expensive than duck down, even at comparable fill powers. We can help you consider the pros and cons of each, but only you can decide how much these differences are worth to you.

ultralight sleeping bag - the econ burrow is a versatile, inexpensive quilt with quality...
The Econ Burrow is a versatile, inexpensive quilt with quality features.
Credit: Ethan Newman

One numerical way to assess value is to compare the overall score we've given a product to its cost. For example, two bags might receive similar scores, but one could cost significantly less. All things being equal, the less expensive option would provide greater value. Without scoring for value, we've highlighted some less expensive options to help those looking to save a bit of cash. The Enlightened Equipment Revelation 20 provides top-notch performance with the fairest price tag. It's not inexpensive, but it does cost significantly less than top-of-the-line products that it directly competes with. The Hammock Gear Econ Burrow comes with a step down in performance, but many people will be satisfied with its performance, especially considering the price savings. This model proves that you can still get a good ultralight model on a tight budget. The Outdoor Vitals StormLoft Down TopQuilt 15F is a good value for someone's first foray into quilts, given its stated limit temperature rating, and the 800+ fill power down it comes with.

ultralight sleeping bag - the rei trail magma 30 quilt can be sealed up quite tight for colder...
The REI Trail Magma 30 quilt can be sealed up quite tight for colder nights using the included pad straps, neck draft tubes, neck cinch strap, and snap located at the top of the quilt. Especially for first-time quilt converts, this bag is a good choice.


No matter how fast and light you go, eventually, you'll have to stop and rest. Getting a good night's sleep is essential to going hard again the next day. A warm sleeping bag is paramount to getting good sleep. Many ultralight hikers consider it the "ultimate layer." If your sleeping system, including your bag, pad, and warm clothes, can't keep you warm enough to recover after a long day, it doesn't matter how lightweight it is.

Fortunately, the bags we tested mostly offer good to excellent warmth-to-weight ratios, using quality materials and clever designs to maximize warmth. You should choose your bag based on the conditions and temperatures you expect to encounter. Because warmth is the main purpose of an ultralight sleeping bag, it counts for 30% of each product's overall score.

Sleeping bags work by trapping many tiny little pockets of air in the insulation, which prevents heat loss to the air around you. Currently, down feathers offer the best warmth-to-weight ratio of the common insulation types. The quality of down is rated according to its fill power, a measurement of the amount of loft a specific weight of down provides. Higher fill power numbers translate to more loft and better warmth-to-weight ratios. To keep the down feathers in place, manufacturers incorporate baffles into their sleeping bags. These are sewn pockets within the bag that ensure the insulation stays where it's supposed to, whether spread evenly or placed strategically. Box baffles, sewn-through baffles, and other designs all have their advantages and disadvantages, but they share the same goal of keeping the down in place.

The other primary type of insulation is synthetic fibers. One advantage of synthetic insulation is that it's a more affordable material that's also easier to work with. Swaths of synthetic batting don't need an intricate system of baffles to stay in place, and if it gets wet, it still retains a significant amount of insulative power. The drawback, however, is that synthetic fibers can't offer the same warmth-to-weight ratio as down. Synthetic insulation is also unable to pack down as small. For these reasons, down is a more popular choice in ultralight sleeping bags, but there are plenty of situations where a synthetic bag could be a better choice.

ultralight sleeping bag - the revelation 20 is the warmest one that we tested, and on a warm...
The Revelation 20 is the warmest one that we tested, and on a warm summer night, there was no need to fasten it up underneath us. Going light, Peter didn't even bother with a sleeping pad, and apparently slept all night with his headlamp on. Beware the power of the "sleep aids" legal in Colorado.

Temperature Ratings

Most sleeping bags and quilts come with a temperature rating recommended by their manufacturer (i.e., 20 degrees Fahrenheit). These numbers, however, rely on the honesty of the manufacturer, and marketing departments usually aren't known for their honesty. On one particularly rough night of "product testing," we slept in two bags, each rated to 15F at around 15,000 ft in Nepal. It happened to snow that night, and the temperature dropped to 10-15F. Wearing all of the clothes they had, two of our testers both spent the night shivering mercilessly and welcomed the 3:00 AM pre-dawn wake-up call to get moving again. These models did not perform well at their stated rating, so what gives?

There is a popular industry-standard test for sleeping bag warmth called EN 13537. For a sleeping bag to qualify for the test, however, it must have a hood. This excludes many of the bags and quilts in our review. If a bag can undergo EN 13537 testing, it receives four ratings, but the two to look at are the "comfort" and "lower limit" ratings. Most manufacturers use the lower limit as their advertised rating, but be aware that the lower limit is defined as "the temperature at which a standard male can sleep in a curled position without waking." The "comfort" rating is the temperature a "standard female" can sleep in a comfortable and relaxed position.

In the case of the two bags we shivered inside in Nepal, the lower limit was listed as the temp rating. Although it's true that we didn't freeze to death that night, we were using the bags well below their comfort ratings in the upper 20s. Focus on these comfort ratings to get a better idea of a more reasonable temp limit. For sleeping bags that don't qualify for or don't receive an EN test, the manufacturers select their own rating to advertise. In the individual product reviews, we have described how these manufacturer ratings compare to a standardized EN rating.

ultralight sleeping bag - letting the down uncompress before a night out in the utah hills. we...
Letting the down uncompress before a night out in the Utah Hills. We recommend unpacking your bag well before crawling into it so that it has time to regain its loft (and therefore maximize its warmth).
Credit: Ethan Newman

The quantity and quality of the insulation are big factors in the warmth of a bag, but we also found that the design can have a huge influence. Features like closed foot boxes, draft collars, hoods, zipper baffles, and pad attachment systems (for quilts) can differentiate products that utilize similar insulation. In general, hooded mummy bags were a bit warmer because they allowed us to burrow deep into the bag. Quilts, in contrast, inevitably allowed cold air to creep into the thermal envelope whenever we moved during the night, so we never seemed to feel quite as toasty.

Insulated Sleeping Pads and Quilts

All ultralight sleeping bags, but especially quilts, are designed to be used as part of a sleep system that includes the bag, a sleeping pad, and your clothing. Tailor your system to work in unison to keep yourself as comfortable and warm as possible. Most tested quilts aren't designed to enclose the user fully but instead attach to an insulated sleeping pad to form a warm envelope. The theory behind quilts is that the sleeper compresses any sleeping bag insulation below them, negating the insulating effect it would otherwise have, so why not ditch this unnecessary material and save weight? This can work well but requires a careful selection of a sleeping pad to match your quilt, and the pad needs to offer great insulation from the ground.

Sleeping pad insulation power is rated on a scale called R-value. The higher the R-value of a sleeping pad, the more insulation it offers from the ground. During our testing on cold nights, we found that some quilts left chilly drafts, and we would have liked some extra insulation below us to fill in these gaps. Make sure your insulated pad fits your quilt and that any extra clothing won't compress the insulation and reduce its effectiveness. Pads do come in different widths, and a wider pad may spread out a quilt too much, leaving less room for you to sleep underneath.

Related: Best Backpacking Sleeping Pad of 2023

We made a point of testing each of these bags while sleeping in temperatures very close to their stated ratings, catching two colds, and spending more than a few nights shivering in the process. These experiences taught us which bags were warm and which were not, and we rated these bags on comparative warmth, meaning the warmest got the highest score and the coldest got the lowest score.

Several bags tied for warmth (in proportion to their rating): the EE Revelation 20, the ZPacks Classic, and the Western Mountaineering Summerlite. The Western Mountaineering bag is a hooded mummy bag that creates a nearly complete thermal envelope around the sleeper, sealing in as much warmth as possible. The Zpacks and Revelation bags were also very warm, but the lack of a hood requires a warm hat or hooded jacket to insulate your head.

ultralight sleeping bag - we saw a wide range of loft among ultralight sleeping bags. six...
We saw a wide range of loft among ultralight sleeping bags. Six ounces of synthetic Primaloft Gold insulation (left) found in the thin Patagonia sleeping bag (from a previous testing) hardly compares to 13 ounces of 950FP goose down (right).
Credit: Jack Cramer

While we love quilts for their versatility and spaciousness in warmer weather, our testing revealed that in cold weather, they don't seem to seal off as well and didn't keep us as warm as mummy-style bags.

The warmest quilt we tested was the Outdoor Vitals Down TopQuilt, which certainly came down to just how much down it packs in its baffles - ounces more than any other quilt in this review. To get the most out of the temperature rating of this bag, it's imperative that you pair this quilt with a down balaclava and warm sleeping pad, as both these influence just how toasty you're going to feel while snoozing.

ultralight sleeping bag - a must-have accessory for a quilt with a limit rating of 15f - like...
A must-have accessory for a quilt with a limit rating of 15F - like the Outdoor Vitals StormLoft, is a proper insulated balaclava which complements the quilt and keeps your head as insulated as your body.
Credit: Justin Simoni

The REI Magma Trail Quilt 30 fared pretty well in our testing when it came to warmth for a quilt but was a bit finicky to set up correctly. Much of its warmth comes from removing features that would ordinarily add to the versatility of a quilt. For example, the Magma's toasty foot box is important for keeping your feet warm, but on a hot night, it lacks the option for any sort of foot ventilation or the ability to transform the entire quilt into a blanket. This may make things a little too toasty in warm summer conditions.

ultralight sleeping bag - the summerlite fluffs up to a warm 4-inch fill and is one of the...
The Summerlite fluffs up to a warm 4-inch fill and is one of the toastiest bags we tested.
Credit: Ethan Newman


What separates this review from our other sleeping bag reviews is the emphasis on weight. Ultralight backpackers are often distinguished from regular backpackers by having a base weight of their overnight pack (non-consumable gear) of under ten pounds. The idea is that by being willing to make some compromises in comfort or convenience, ultralighters can enjoy the considerable benefits of a light pack. A ten-pound base weight can be achieved with any of the products in this review, but if you're going super ultralight, pay extra attention to the weight score. As the second most important metric, weight accounted for 25% of a product's final score.

ultralight sleeping bag - weight is a critical aspect of any outdoor gear, but it&#039;s...
Weight is a critical aspect of any outdoor gear, but it's particularly important to ultralight travelers.
Credit: Jack Cramer

It is worth noting that in almost all cases, we chose the option or version of each model that was the lightest weight, usually going with a higher temperature rating to do so. For those who want a bit more warmth and are willing to carry a few extra ounces to have it, there are usually slightly heavier and warmer options available. Many of the products we tested have an incredible spread of parameters you can customize, including overfilling the bag or adding draft tubes. These options can significantly affect the warmth of the bag but may delay your order and add to the product's price.

When it comes to ultralight sleeping bags, most managed to shave weight with a combination of high-quality insulation and pared-down features and design. Down provides one of the best warmth-to-weight ratios, which is why it is the insulation of choice in the very lightest products. Down is rated by its fill power, and the higher the number, the more loft it has, and thus the higher quality. In most cases, the bags tested in this review use down with a fill power of 800 or more. The fill power and quantity of down used in each competitor can be found in the specs listed for each product.

ultralight sleeping bag - not all ul sleeping bags pack down equally!
Not all UL sleeping bags pack down equally!
Credit: Ethan Newman

In the case of most quilts, weight is saved by eschewing fabric or insulation on the underside of the bag. Lightweight straps or string systems help latch the sides of the quilt around the user or a sleeping pad, thereby eliminating the weight of a zipper as well. Quilts also forego a hood, thus avoiding the weight of more fabric and insulation. Some models also feature snaps to wrap the quilt around one's neck while sleeping — a nice feature, but it can increase weight.

Mummy bags, on the other hand, employ other tricks to save weight. Ultralight fabrics, both on the shell and baffles, reduce weight but usually make the bags more delicate. Smaller zippers have the same effect. Zippers are also often shortened to trim ounces at the sacrifice of venting possibilities. Most ultralight mummy bags have rather narrow dimensions because less fabric is needed so that the bag can be further lightened.

When calculating the overall weight of your sleep system, factor in how versatile your sleeping bag and quilt might be for different tasks. Quilts and full zip sleeping bags can keep you warm on cold mornings as you get ready for the day's hike, which may mean you can optimize your clothing layers better. If you'll require additional warmth for your head at night, as most quilt users will probably want, find a nighttime insulated cap that can play double-duty while out on the trail.

ultralight sleeping bag - the vesper 32 is impressively light and packable at 15 ounces, but...
The Vesper 32 is impressively light and packable at 15 ounces, but the compression sack made concerning ripping noises when we tightened it down. Not an issue if you simply stuff this bag into the bottom of your pack sans sack.
Credit: Ethan Newman

We weighed these bags on an independent scale to determine the weight and then assigned the scores comparatively. In the case of quilts requiring extra straps or buckles to close up the quilt or affix it to a sleeping pad, we also included that weight. However, we chose to weigh any included stuff or compression sacks separately.

One stand out in this metric is the Sea to Summit Spark 40 mummy bag. It comes in at an insane 12 ounces and packs down to the size of a water bottle. To achieve this impressive weight, it eschews baffles for a sewn-through design to keep the insulation in place. This construction, however, is less thermally efficient because it creates uninsulated zones at the seams.

The Western Mountaineering HighLite throws many ultralight tricks at the problem of shaving grams, including using lofty, 850+ down, half zips, and thin fabric material to create a bag that weighs in at around 15 ounces. For quilts, the Big Agnes Fussell UL Quilt uses a very minimal design that's more blanket than a usual backpacking quilt with its hyper-minimal footbox. It employs snaps instead of pad straps to shave a few more grams from the design and comes in at around 17 ounces.

A unique flyweight design weighing in at 16.4 ounces is found in the Feathered Friends Vireo UL, which is designed to have far less warmth in the top portion of the bag to then be supplemented with an additional insulation layer you're already packing. This design decision follows the UL ethic of prioritizing items that have multiple uses to save weight across your entire pack system.


The other half of the equation for a good night's sleep is comfort. Things like drafts, drawcords dangling in your face, buckles wedged underneath you, or a claustrophobic shape can all prevent you from sleeping soundly. And if you sleep well, you should be able to perform better the next day. There's nothing worse than loathing getting into a subpar sleeping bag or quilt, which is why comfort is important enough to make it 20% of the overall score.

When assessing for comfort, the first thing we looked at was how well the bag fits. Our head testers are 5'11" and 5'8" and fairly trim, so we ordered all of the test models to suit a person 6'0" tall and standard width. By ordering them all the same size, we could compare each bag's fit to the same standard. Luckily for you, most of the bags in this review come in different height and width options, making it easy to customize a bag for your particular shape.

Two aspects of a sleeping bag or quilt's fit were immediately noticeable: the length and the width. Despite many being marketed for a 6'0" person, some bags were too short, leaving it uncomfortable to cinch the collar over the shoulders or wear the hood over our heads.

ultralight sleeping bag - waking up to a chilly morning after sleeping out in the san juan...
Waking up to a chilly morning after sleeping out in the San Juan Mountains. The Vireo, in blue, and the HighLite in purple.

Rather than reduce the length, most ultralight quilts reduce the width to minimize weight. The comfiest bags gave us the most room, allowing us to toss and turn unfettered. Mummy bags are historically claustrophobically cut. But some, like the Feathered Friends Vireo UL, were generously fit. Quilts, on the other hand, offer plenty of room but sometimes yield claustrophobic feelings when we utilize their pad attachment systems. Some quilts were too narrow to wrap ourselves in on chillier nights, no matter how much we repositioned.

The little details can detract from or enhance comfort. For example, the position of drawstrings, the feel of a fabric, or the shape of the hood can make or break a good night's sleep. All these small elements also influenced the comfort score of each product.

Ultimately, the Feathered Friends Vireo UL scored as the most comfortable sleeping bag or quilt. Its vast and spacious cut in the torso is designed to accommodate the extra fill of an insulated jacket, but it also left us feeling free to move about as desired. Many other bags/quilts scored just a little lower, including the Sierra Designs Cloud 35, which was unique out of all the sleeping bags we've tested in that it does away with a zippered design completely. Instead, it uses an extra-wide comforter for you to wrap your body around.

ultralight sleeping bag - the sierra designs cloud 800 35 unique zipperless design makes it...
The Sierra Designs Cloud 800 35 unique zipperless design makes it easy to get into and out of the sleeping bag

The REI Co-op Magma 30 also scored quite well. A standout feature of this bag is its 63" shoulder girth, which is certainly welcome for us, shoulders chiseled from rock climbing all day. None of the other top models of sleeping bags/quilts we tested had outstanding comfort scores. This doesn't mean they're uncomfortable, but it highlights that comfort compromises are made to keep sleeping bags ultralight. If the compromises we've documented across all these products in the name of wearing the coveted "ultralight" label are too much, consider a more traditional backpacking sleeping bag.

Related: Best Backpacking Sleeping Bag

ultralight sleeping bag - for warmer nights, the rei trail magma 30 quilt can be loosely...
For warmer nights, the REI Trail Magma 30 quilt can be loosely fitted to the pad using the included pad straps, and left open at the top of the quilt.


If you want a three-season sleeping bag, or are planning an epic six-month thru-hike that will span the seasons from cool spring into hot summer and back into a cool fall, then versatility is a critical metric. Versatility is the ability of the bag to be used comfortably in a variety of situations. Questions we asked ourselves when rating each bag for versatility were: is it possible to wrap oneself up like a cocoon to stay warm on the coldest nights? Likewise, is it feasible to open the bag up and ventilate to stay cool on the warmest of nights? Sleeping bags that could do both with ease were the highest scorers when it came to versatility, and sleeping bags that pigeonholed themselves into only being practical in one season or temperature range scored the lowest.

In general, quilts are more versatile than ultralight mummy bags, whose half-length zipper designed with weight savings in mind often made it even harder to ventilate on warm nights. Quilts and bags that included full-length zippers, or quilts that were long enough and broad enough to wrap oneself up fully, fared the best because they most easily allowed for staying warm on cold nights. Besides just being able to be used in both hot and cold seasons, we also looked at whether a bag would be serviceable in wet climates. Ultralight bags that used synthetic insulation, which will not clump and will continue to provide substantial insulation even when wet, received a bonus.

ultralight sleeping bag - our testers enjoying themselves while comparing/contrasting the...
Our testers enjoying themselves while comparing/contrasting the versatility of the products. Being able to poke your feet out of the bottom of a sleeping bag allows you to walk about your campsite while staying wrapped up on cold mornings.

We also looked at whether a bag used a DWR (durable water repellent) treatment on its outer shell to protect it from absorbing liquids such as condensation, or used a naturally water-resistant fabric such as Pertex Quantum to accomplish the same thing. Lastly, we looked at how packable a sleeping bag was. The smaller it packs down, the easier it is to carry along with you, and for a few outdoor sports like bike touring or bike packing, this is a critical component of whether a piece of gear can be useful or not. As an important metric, but not the most crucial metric, we weighted versatility as 15% of a product's final score.

ultralight sleeping bag - on a chilly morning in the desert, we enjoyed the versatility of...
On a chilly morning in the desert, we enjoyed the versatility of being able to wear the Flicker 40 with our feet out and the zipper done up, at least until the sun hit.

The most versatile product without a doubt is the Feathered Friends Flicker 40 UL. This bag can transition seamlessly between use as a quilt or a fully enclosed hoodless mummy bag, offering protection for a variety of situations. On the warmest nights, it can be used as a spread-out blanket, which is also ideal for two people, or as a quilt with an enclosed foot box by tightening the drawstring on the end and zipping it up partway. The full-length zipper means that on cold nights, it is possible to seal it up entirely and trap the warm air in with the help of a neck baffle with dual drawcords. No other bag so easily met the demands of all seasons. Although we tested the 40F version of this bag, it also comes in 30F and 20F versions for those who live and play in colder climates or seasons.

ultralight sleeping bag - the flicker 40 is one the quilts in the review that is capable of...
The Flicker 40 is one the quilts in the review that is capable of opening up fully into a blanket on warmer nights. It's wide enough for two people to fit under.

Also near the top in the versatility department is the Zpacks Classic. This hoodless mummy bag is rated to 20F and features box baffle construction and a DWR coated Pertex Nylon shell. It's ideal for cold nights. It also has a ¾ length zipper that allows one to open it up like a quilt for warmer nights. If you want an ultralight bag that you can utilize in all three seasons, be sure to pay attention to our versatility ratings.

ultralight sleeping bag - one of the nice things about quilts is how easily they function as...
One of the nice things about quilts is how easily they function as blankets to keep one warm while hanging out around camp.


The features metric is the last piece of the puzzle to understand how well an individual ultralight sleeping bag works. A sleeping bag is simply a down-filled sack or blanket designed to keep you warm at night, and the features are all those little components that make it work. Drawstrings, draft collars, zippers, and hoods are all designed to enhance a sleeping bag's functionality and make it a more useful addition to an efficient sleep system that conserves all the necessary BTUs you produce to sleep soundly.

The most common features found on these bags are zippers, draft collars, cinch cords around the neck, face, hood, or feet, and in the case of quilts, pad attachment systems. When assessing for features, we looked first at whether a bag's specific features functioned well or whether they were finicky and annoying. Then we compared them to similar features on the other bags and rated them in comparison to all the others.

ultralight sleeping bag - the unique designs of the sierra designs cloud 800 do take a fair...
The unique designs of the Sierra Designs Cloud 800 do take a fair bit more material and stitching when compared to other bags we've tested.

Zippers that wouldn't stay zipped or were continually getting stuck in fabric, pad straps that wouldn't stay attached or wouldn't lock in place, and drawcords that didn't have buckles or wouldn't stay tight, are examples of poor-performing features that caused us to knock the score down a bit.

The Feathered Friends Hummingbird UL 30 tries to solve many of those annoying zipper problems by employing a flexible piece of plastic by the zipper, to stop the fabric from being sucked into the zipper and stuck.

And once again, the Flicker 40 receives the highest score for features. Not only did it have a ton of features — full-length zipper with a reinforced draft tube, drawcord enclosure at the feet, dual drawcord and neck baffle at the head, optional attachment points for DIY pad straps — but they all worked well. The difference in having a full zipper versus just intermittent buttons or straps to enclose the quilt turned out to be a game-changer for trapping in heat.

Showing the neck collar and dual draw cords that can each be...
Showing the neck collar and dual draw cords that can each be tightened to seal off the warmth envelope on a cold night.
This is the foot box of this quilt, tightened all the way up for an...
This is the foot box of this quilt, tightened all the way up for an enclosed foot box in mummy bag mode. Also shown is the zipper which runs full length.

The Sierra Designs Cloud 35 also had a great set of unique features. In fact, this sleeping bag seemed to really want to shine in a category all of its own between a sleeping bag and quilt. Zippers getting stuck within the shell fabric of the bag itself will never be a problem because there are no zippers to get stuck! Along with a full zipperless design, the Cloud 35 has an interesting footbox vent, and an oversized quilt useful for either keeping loose on warm nights or tight on colder ones. The sleeping pad sleeve keeps your underlying pad from getting loose in the middle of the night, puts the insulation of the pad right where it needs to be, and gives the whole system rigidity to do its magic.

The Revelation 20 also has a great set of features, including a cleverly designed and versatile footbox that both vents and allows the entire quilt to transform into a blanket. Its warmth to weight ratio, especially when compared to its price for a US-made quilt, is also quite remarkable, and makes it worth your time to consider.

ultralight sleeping bag - a warm night in the black canyon was a great excuse for cowboy...
A warm night in the Black Canyon was a great excuse for Cowboy camping in the Katabatic Gear Palisade 30. We loved the adjustability of the pad attachment straps on this pleasant evening.


Sleeping bags have been around for a long time now, and the market is flush with options for use in or outside of a tent. Everything from old-school, square-cut monstrosities to airy space-age quilts and everything in between. For this review, we specifically singled out ultralight sleeping bag and quilt options because the world of backpacking is only getting leaner as companies shave down the ounces in their gear and people start appreciating a more fast and light approach. Ultralight sleeping bags are best suited for warmer temperatures, but with proper planning and well-designed systems, they can be pushed into the shoulder seasons. These types of bags are for people who want to move quickly through the mountains without the added weight of a bulky bag. Activities like thru-hiking, fastpacking, bikepacking, alpine climbing, adventure racing, and bike touring all employ ultralight systems to go further and faster in the wilderness. With our extensive comparison of the best models of ultralight sleeping bags and quilts on the market, we hope you find the right choice for your backcountry adventures.

We poured over scores of ultralight sleeping bags and quilts to find the best models and put them to the test, from mountains to deserts to forests to give you the best recommendations possible.

Andy Wellman, Ethan Newman, Justin Simoni, and Jack Cramer

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