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The Best Ultralight Backpacks of 2020

The Mariposa out for a few days hiking through the backcountry of Grand Teton National Park. The pack has ample room in the side pockets for stoves  bottles  and food  while the mesh pocket is large enough for a few extra layers.
Wednesday February 26, 2020
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After the best ultralight backpack for your next adventure? We've tested 25+ products over 5 years, wading through the countless options available on the market. For our 2020 update, we bought 14, putting them through hundreds of hours of side-by-side testing on treks around the world. From the JMT, to the Haute Alpes in Southern France, to the Appalachian Trail, each contender has been subjected to a variety of metrics, such as weight to volume ratio, and features, to identify the best of the best. With the ultralight world growing increasingly more competitive, we've done the work for you, highlighting the top performers, as well as niche products, and budget-friendly models.

Top 14 Product Ratings

Displaying 1 - 5 of 14
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Best Overall Ultralight Backpack

Gossamer Gear Mariposa

Editors' Choice Award

$270 List
List Price
See It

  • Weight-to-Volume Ratio - 35% 7
  • Comfort to Carry - 25% 10
  • Features - 20% 10
  • Adaptability - 10% 8
  • Durability - 10% 9
Total Weight: 30.5 oz | Average Weight-to-Volume Ratio: 14 g/L
Comfortable with a variety of load sizes
Highly adaptable
Thoughtful feature set
Fits bear canister
On the heavier side

For years, the Gossamer Gear Mariposa has been the leader of the "pack" among our ultralight contenders. The combination of comfort and features makes it easy to carry, whether you're headed out on a longer adventure or using it as a day pack. The feature set includes just enough pockets to keep you organized and to allow for lots of external carrying options without overwhelming the user. We especially like the stretchy kangaroo pockets on the outside for extra layers or wet gear. The Mariposa also carries a bear canister with ease, which is impressive for a pack of its relatively compact size. We were also impressed with the overall durability of this pack, especially since the fabric used in its construction appears to be thin and lightweight. Even after miles of bushwacking and rock abrasion, this pack barely got a scratch.

The Mariposa is a 60-liter pack, and you can carry up to 64 liters in it if you want to. That's great if you're loaded down, but part of the UL mission is to pare down the weight and size of your gear, and we didn't always need that much room. While the Mariposa isn't the absolute lightest model in our review, the 2.5 pounds total weight and 14 g/L weight-to-volume ratio is still impressive, and those extra ounces gave us more comfort on the trail than any other option.

Read review: Gossamer Gear Mariposa

Best Bang for the Buck

Osprey Exos 48

Best Buy Award

at Backcountry
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  • Weight-to-Volume Ratio - 35% 4
  • Comfort to Carry - 25% 9
  • Features - 20% 8
  • Adaptability - 10% 7
  • Durability - 10% 8
Total Weight: 37.6 oz | Average Weight-to-Volume Ratio: 17 g/L
Good for medium loads
Most complete set of features
External storage and lashing options
Heavier than others
Not as durable as others

Though you can still find cheaper packs in this review, the Osprey Exos 48 combines durability and great features with a relatively affordable price tag, earning it our Best Buy Award. It really is the features that make this pack stand out. Its variety of pockets, straps, and attachment points allow for plenty of creativity if tinkering is your thing, yet its classic, user-friendly aesthetic works as is for those who don't feel the need to modify. The Exos carries loads over 20 pounds with ease and excels when loaded down over 30. The suspension and ventilation of the back panel provides a comfortable, breathable carry for longer missions.

The Exos weighs in at 2 pounds 5.6 ounces, just making the cut as an ultralight pack. It has one of the higher weight-to-volume ratios in our review, but it still stands apart from the majority of traditional backpacking packs. Its carrying capacity is relatively small (48L), which caters to those with an already trimmed-down kit. We were a little concerned with the long-term durability of this pack, as the stretchy side pockets quickly got holes. The Exos is a tried and true favorite that has been around for a while; this means it is widely available online and in stores and is easy to pick up and take out on your next weekend adventure.

Read review: Osprey Exos 48

Best for Ultralight Enthusiasts

ZPacks Arc Blast 55

ZPacks Arc Blast 55
Top Pick Award

$325 List
List Price
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  • Weight-to-Volume Ratio - 35% 10
  • Comfort to Carry - 25% 7
  • Features - 20% 5
  • Adaptability - 10% 5
  • Durability - 10% 6
Total Weight: 21.3 oz | Average Weight-to-Volume Ratio: 11 g/L
Extremely light
More or less waterproof
Lots of external storage options
Lightweight frame
No hip belt pockets (available add-on)
Complicated frame
Very specific

The ZPacks Arc Blast 55 is a unique and highly specific pack in that it weighs almost nothing, yet still can carry over 20 pounds. With a measured weight of 21.3 ounces, the pack is a great deal lighter than most in this review. Compared to our Best Buy Winner, the Osprey Exos, the Arc Blast is a full 16.3 ounces (just over a pound) lighter. Made from Dyneema Composite Fabric (DFC), it's incredibly durable, though the fabric is a bit stiff and crunchy. Beware of sharp metal edges though (bear canisters or climbing gear), since they can easily wear through the fabric. Though the pack has been slightly updated this past year — a few changes to the straps, pockets, and waist belt, as well as an increase 52L to 55L. Even with these changes, we love the updated Arc Blast enough to give it an award for those serious about going light.

To reiterate, the Arc Blast is a slimmed-down ultralight machine, with no bells or whistles on this particular model. The frame is super-light and super-complicated; we do not recommend removing it unless you want to spend a few hours reassembling the pack. The only way to fit a bear canister in this slender pack is vertically, which makes it a bit less efficient to pack. We would recommend this pack to any experienced ultralighter looking to strip a few ounces off their Big Four base weight.

Read review: ZPacks Arc Blast 55

Best for a Small Capacity Pack

Ultralight Adventure Equipment CDT

Top Pick Award

$145 List
List Price
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  • Weight-to-Volume Ratio - 35% 8
  • Comfort to Carry - 25% 6
  • Features - 20% 8
  • Adaptability - 10% 8
  • Durability - 10% 9
Total Weight: 24 oz | Average Weight-to-Volume Ratio: 12.8 g/L
Simple feature set
Full-sized, comfortable waist belt
Relatively small volume
Thin, unsupportive shoulder straps
Foam pad falls out easily

Ultralight Adventure Equipment consistently makes top-notch gear for the ultralight enthusiast, and the CDT is the latest addition to their fleet of durable, lightweight, hardworking packs. This pack is smaller than the previous we've have tested from ULA, but still has many of the signature features that make these packs so well-loved. With a frameless design (a small foam panel for support in the back), the CDT is meant for relatively light, small loads. That said, the waist belt is comfortable, and the materials used in the construction are rugged enough to handle the inevitable beat-down on the trail. Because of its size and design, it's ideal for loads under 20 pounds and will start to feel uncomfortable with a load over 25 pounds.

What's not to like, you ask? Though we loved the feature set of the CDT, it is relatively minimal. This pack is definitely designed for folks who don't like extra frills — there are minimal pockets and external storage options. The cinch top closure also takes some getting used to (imagine a simple stuff sack) and does not completely protect from the elements. We loved this pack for short trips and light travel, plus its price tag is approachable, which is an added plus.

Read review: Ultralight Adventure Equipment CDT

Why You Should Trust Us

Jane Jackson and Brandon Lampley spearheaded this review, bringing to the table a wealth of related experience. 200+ days a year, you can find Jane outside using and testing gear. With years spent working and playing in the Yosemite backcountry, the Tetons, and the Wind River Range, as well as trips taken to the Alaska Range and the Himalaya, Jane has spent plenty of time under the burden of a heavy pack. Brandon has hiked both the Pacific Crest Trail and Appalachian Trail, essentially back-to-back, with only four months off in between. He also has first ascents to his name in the Indian Himalaya and has summited Denali and Ama Dablam.

Our testing protocol consisted of both lab testing and trail miles. We made sure to independently test weight and volume measurements, as manufacturers have been known, at times, to fudge these numbers in their favor. We also took it a step further and scored packs based on their weight per unit volume, which allows us to compare models of different volumes fairly. On-trail testing included trips such as 260 winter miles on the AT and 40 miles in the Black Rock Canyons Wilderness in Colorado. Additionally, 15 and 30-pound test weights were used for shorter test laps for more direct comparison.

Related: How We Tested Ultralight Backpacks

Virga and Exos tested side-by-side.

Analysis and Test Results

Out with the old, in with the new. In this case, the new means a sleek ultralight backpacking pack to replace that old full-frame monster of a pack that's collecting dust in your garage. The competitors we evaluate here include the best and most versatile packs for lightweight and ultralight three-season backpacking, as well as a couple more specialized models for specific uses. The top models are all great choices for thru-hiking trips that last for months and shorter trips as well and expert backpackers will also find these packs just large enough for wintertime adventures. Read on to learn more about how we scored the packs across the test metrics and to find the top performers in each one.

Related: Buying Advice for Ultralight Backpacks

The Gossamer Gear Gorilla packed with equipment  food  and fuel for a five-day wintertime section of the Appalachian Trail. We covered a lot of miles to find the best ultralight backpacks. From the packing tests seen here  to the independent weight and volume measurements in our lab  we've done the most thorough side-by-side testing for you.
The Gossamer Gear Gorilla packed with equipment, food, and fuel for a five-day wintertime section of the Appalachian Trail. We covered a lot of miles to find the best ultralight backpacks. From the packing tests seen here, to the independent weight and volume measurements in our lab, we've done the most thorough side-by-side testing for you.


We often trade off one thing for another when making an outdoor gear purchase, and no one understands trade-offs better than an UL enthusiast. How much can we strip away from our base weight on the trail and still survive? The weight savings that you can achieve in a pack often come at the expense of something else; for example, the Granite Gear Virga 2 was one of the lightest options (10 g/L) but was also one of the least comfortable to carry a lot of gear with. If you are looking for a good deal on a pack, but don't want to trade-off too much on the performance end, check out the Osprey Exos 48, our Best Buy winner, and our runner-up, the Mountainsmith Scream 50. Both of these packs provide ample support and weight a bit more than other packs in this fleet, so consider the Granite Gear Virga 2 for an incredibly light, and inexpensive model.

Weight-to-Volume Ratio

Weight-to-volume ratio is a measure we use here at OutdoorGearLab to compare packs and luggage of differing volumes. This heavily-weighted (no pun intended!) metric gets straight to the point…how much does this pack weigh relative to the volume it carries? Two sets of data, generated by our lab measurements, comprise this metric. First, we measured the weight of each model on our digital scale. Then, we weighed each pack with all modular components in place. Next, we examined each for a frame, waist belt, or other pockets that can be easily removed to pare the weight down for light loads; we then stripped these features off of each pack and weighed them again.

The most detailed lab testing with these products is our independent measurement of pack volume; since nominal volume measurements from manufacturers are difficult to compare, we decided to perform our test. Although an ASTM standard exists for measuring pack volume and many pack manufacturers perform ASTM testing, some report the capacity of only the main pack as the nominal measurement, while others include pockets. The ASTM test doesn't provide for measuring external pocket volume, which is significant on these packs. In our experiments, we measured the volume of the main pack, the main exterior pockets, and the lid (when present).

After we filled the main compartment of each pack with ping pong balls to measure volume  we then measured the volume of external pockets and lids. We found all the top performing packs have similar total volume measurements.
After we filled the main compartment of each pack with ping pong balls to measure volume, we then measured the volume of external pockets and lids. We found all the top performing packs have similar total volume measurements.

To provide an example, the Gossamer Gear Mariposa is described nominally as a 60-liter pack and the Haglofs L.I.M. Strive as 50 liters. However, we found these two models were nearly identical in volume, both when performing our laboratory volume testing with ping pong balls and when packing in the same kit for a five-day wintertime trip on the Appalachian Trail. The weight-to-volume ratio is the most significant contributor to total scores, accounting for 35 percent. The Gossamer Gear Mariposa, the Granite Gear Virga 2, and ZPacks Arc Blast 55 earned the best scores; these are the three are the lightest packs we tested and forego many of the features that are common on other models. By combining an incredible weight-to-volume ratio with a surprising level of carrying comfort, the Arc Blast won our Top Pick Award for Ultralight Enthusiasts.

The ULA Circuit and ULA CDT earned the next best scores for weight-to-volume ratio, and they each measured a tiny bit better than the middle of the field with all their modular components in use. Both were also top performers when we compared "stripped weight" to "stripped volume." We were especially impressed by the ULA Circuit, which has a larger carrying capacity than the CDT. Unlike the Granite Gear Virga 2 or the ZPacks Arc Blast, both of these are fully-featured with hip belt pockets and can carry heavier loads in more comfort.

The Hyperlite Southwest provides durability  water resistance  and a solid design.
The Hyperlite Southwest provides durability, water resistance, and a solid design.

Carrying Comfort

Of course, we all want an ultralight pack to be featherlight, but it must carry our load comfortably to be worth it. For each of these packs, we judged load-carrying comfort for two loads: 15 lbs and 30 lbs. We then averaged each pack's performance in both categories to generate our carrying comfort score. Fifteen pounds is a perfect comparison weight for ultralight hikers on a short trip, while thirty pounds is a fair comparison weight for lightweight hikers on shorter trips, ultralight hikers carrying a week's worth of food, or for those brave enough to travel in the winter. While some packs are capable of being stripped of their frame and waist belt, our evaluation of "great, good, or poor" for carrying 15 lbs and 30 lbs is with the frame and waist belt in use. We would recommend stripping down a pack completely when carrying 12 pounds (or less) total weight.

The Gossamer Gear Mariposa, Gossamer Gear Gorilla, and the ULA Ohm 2.0 earned our highest scores in this category, for carrying both 15 and 30-pound loads. Also, these three packs are the easiest to strip of frame and waist belt if and when you want to take 12 pounds or less. At this low weight, we feel frames, and even waist belts are not necessary.

Nearly every day out with these packs  we put them on the scale before hiking  noting how well each carries 15 or 30 pounds (and the loads in between). At the end of our testing period  we also loaded each pack with 30 pounds  and hiked the same hill up and down to confirm our field testing.
Nearly every day out with these packs, we put them on the scale before hiking, noting how well each carries 15 or 30 pounds (and the loads in between). At the end of our testing period, we also loaded each pack with 30 pounds, and hiked the same hill up and down to confirm our field testing.

Also notable in this metric are the next highest scorers. The Osprey Exos 48 carries 30 pounds more comfortably than any other we tested, but we found the tensioned frame a bit "turtle shell-like" for much lighter loads. Other slightly heavier models, like the Mountainsmith Scream 50 scored highly in the comfort metric due to their ample padding and suspension systems.

To simplify our findings for load carrying comfort even further, we've broken down each of our three award winners' niches as far as load-carrying comfort goes:
  • Best for 10-20 lb loads: Top Pick for Ultralight Enthusiasts: ZPacks Arc Blast 55
  • Best for 15-25 lb loads: Editors' Choice: Gossamer Gear Mariposa
  • Best for 20-35 lb loads: Best Buy: Osprey Exos 48


Manufacturers constantly seek to find the right balance of features for ultralight backpacks. Eliminating most creates a very light pack, but including the right features can greatly increase comfort, versatility, and ease of use. Some of the lighter full-sized packs we tested like the ZPacks Arc Blast and Granite Gear Virga 2, both earned top scores in our weight-to-volume ratio metric. Their total scores reflect the trade-offs required to be the lightest: reduced load-carrying comfort at heavier weights and reduced ease of use as a direct consequence of eliminating features.

Many of the newer packs we have added, like the Gossamer Gear Murmur, the ULA CDT, and the Hyperlite Mountain Gear 3400 Southwest 55 have a similar feature set including a roll-top closure and three external shove-it pockets on the outside. Manufacturers seem to be trending in this direction, so consider that when looking at new packs, as lids are seemingly becoming a thing of the past.

We provide a thorough description of each pack's features not covered elsewhere. When covering big miles on the trail, features like easily accessible side pockets for your water bottles, waist belt pockets for snacks, and a convenient place to keep maps handy are a huge benefit. This is also where we detail how each pack accommodates a hydration bladder and just how much stuff you can stow in the exterior pockets.

We love having easy access to snacks and layers.
We love having easy access to snacks and layers.

The Osprey Exos 48 incorporates so many features and its head and shoulders above the rest. While most manufacturers pick and choose which elements they think are the most useful, Osprey provides nearly every storage, lashing, and compression feature you can imagine. This is super convenient but contributes to the pack's relatively heavier weight.

The Gossamer Gear Mariposa also earned top scores in this category with its well-placed side pockets, over-the-top closure mechanism, and large mesh back pocket. Additionally, the ULA Ohm 2.0 received high scores in this metric, though the Gossamer Gear packs both have a large external back pocket, which the OHM 2.0 lacks. We love how much you can stuff in the Gossamer Gear pack pockets compared to the small volume of the Ohm's exterior pocket.

Large external storage pockets are a classic feature common among ultralight packs.
Large external storage pockets are a classic feature common among ultralight packs.


While our carrying comfort metric is focused on how well each pack can carry either 15 or 30 pounds in its full configuration, our adaptability metric focuses on other considerations when you may want to scale your pack up or down in carrying capacity. While on a thru-hike or a week-long adventure in the backcountry, your total bulk and weight will fluctuate up and down between re-supplies, and for weekend trips sometimes you'll need to carry a substantial load, but other times you may carry very little. A pack whose design allows the frame and waist belt to be easily removed for very light loads is more adaptable.

While many of our testers have several packs suited for varying loads, a highly adaptable contender is critical when you seek one backpack to do it all. The Haglofs L.I.M. Strive 50 received high scores in this category due to its easy-to-remove frame and simple design. These features allow it to carry minimal weight, or be packed up with a massive load easily. The pack's overall design is versatile, too; we found it served its purpose as a lightweight mountaineering pack and was a fully functional pack for backpacking.

While stripping the pack down is an excellent feature for light loads, a kit that allows you to strap bulky but light items to the outside is a bonus when you need to carry big loads. Each of these competitors has multiple ways to add things, like a closed-cell foam pad, to the outside. And while in general, we are not a big fan of lids for ultralight packs, they do create one key advantage: the ability to carry bulky items on top of the main compartment secured under the adjustable lid. The Osprey Exos 48 and the Hyperlite Mountain Gear 3400 Southwest both earned a top adaptability score because of their ability to carry heavy loads well with tons of external lashing options. The Hyperlite pack also has a very tall roll top, similar to the one found on the ULA Circuit, that provides a great place to store extra bulky items when a significant food resupply occupies the main pack.

Our adaptability score also considers ease of use with a bear canister. This will be irrelevant to some, but bear canisters are required by regulation on some portions of the PCT and AT. The BearVault BV500 is perhaps the most common bear canister used by weight-conscious hikers in areas where bear-proof food storage is required in the backcountry. We loaded each pack up with a standard three-season kit and five days of food in the BV500 to see how well it fits inside and how much room is left over for the rest of your stuff. If you regularly carry a bear canister of this size, the Hyperlite Mountain Gear Windrider and the Gossamer Gear Mariposa are compatible with this can.

The very tall top of the Windrider 3400's main pack allows you to scale up and down in pack volume. When you go big  you will want your lightest bulky items up top.
The very tall top of the Windrider 3400's main pack allows you to scale up and down in pack volume. When you go big, you will want your lightest bulky items up top.


How durable can a sub-two-pound backpack be? The answer is that most are surprisingly durable. That said, many of these packs require a little more care and attention than load monsters that weigh five or six lbs and use much heavier fabrics and frames. If you plan to carry more than 30 pounds most of the time, the packs in our backpacking backpack review will serve you better. So how durable should an ultralight backpack be? As a baseline, to achieve an above-average score, we estimated that a pack must last for a least one thru-hike of a trail like the PCT or Appalachian Trail. The best of these packs will see you through many thousands of trail miles!

Many factors go into our rating for durability, which contributes 10% of the total scores. First and foremost, we consider the types of fabric used for the main body of the pack and the exterior pockets. All of these areas are subject to abrasion, especially the pockets (if you tend to stuff a lot into them). There are always trade-offs in design; for example, incredibly light main pack fabrics are less durable than robust 200 Denier nylon ripstop fabrics.

The main fabric of the ULA Circuit is likely the most durable over the long haul, but its carbon frame is a liability for rough handling. Our durability rating also considers frame durability and pocket fabrics.

Additionally, the stretchy exterior pocket fabrics that we love for function tend to be more prone to snagging on tree limbs or abrading on rock in comparison to non-stretchy pockets. Unfortunately, it seems that you can't have it all. In our experience, a stretchy main exterior pocket with durable side pockets is the best compromise. This type of design is found on the award-winning Gossamer Gear Mariposa. When it comes to materials, the Gossamer Gear Murmur is made of the most delicate we've seen in this review, and that should be considered when thinking about this product.

While it is the case that you'll need to treat your pack nicely (it is your home on your back!), we also take into consideration whether sitting on it while it is loaded or rough handling in the back of your van or truck could break the frame. To this end, we think that if you are focused on durability or if you are known to be rough on your gear, you should choose a pack with an aluminum frame versus carbon fiber. The rugged aluminum frame is one of the many small factors that lead us to prefer both of the Gossamer Gear packs to the two ULA packs. The carbon rod frame found in the ULA Ohm 2.0 and the ULA Circuit is significantly more fragile. Out of our top scorers, the Mariposa and Windrider are the two models we felt comfortable sitting on without the worry of breaking something.

Durability should be taken into account when comparing the price  weight  and construction of a pack.
Durability should be taken into account when comparing the price, weight, and construction of a pack.

Key Accessories

A rain cover for your backpack has long been one of the key accessories to ensure your ultralight backpacking kit stays dry through rainstorms. The Gregory Octal's UL Raincover is a reliable and widely available choice, as are the covers from Sea to Summit.

Each of these packs comes with its own unique feature set  its up to you to decide what features are important to you.
Each of these packs comes with its own unique feature set, its up to you to decide what features are important to you.

Waterproof roll-top style dry bags or Cuben stuff sacks are an excellent choice for both organization and moisture protection inside your backpack. Sea to Summit's ultralight Sil-Nylon bag is also an ideal choice. For those seeking to shave off the grams, Hyperlite Mountain Gear, ZPacks, and several other ultralight manufacturers produce a large variety of Cuben fiber storage and stuff sacks.

Lining your backpack with a contractor's plastic garbage bag, or better yet a trash compactor bag, has long been a great option to ensure your kit stays dry during long rainy days on the trail. While one of these should last you for a week or more with a little care, you would replace it often while thru-hiking. Cuben fiber pack liners are the state-of-the-art in super light and durable waterproof pack liners. The models available from ZPacks are the best we've seen.

An ultralight backpack is just one of the many products featured in our Dream Backpacking Gear List. Check it out for all of our "dream" backpacking gear and clothing in one spot!

If you're interested in cutting weight even further, you can use a sleeping pad as a back pad in a frameless backpack.


There are a lot of advantages to going ultralight, and we hope these analyses and assessments will help you drop weight in your kit without sacrificing the features you love. While low weight is key, it's not the only piece of the puzzle. We've put several packs to the test, and also offer a backpacking, mountaineering, and day pack review to suit any adventure.

We hiked high and low  from the Continental Divide to the Appalachian Trail  to find the best ultralight backpacks! Here  our lead tester  Brandon  celebrates another beautiful day in Rocky Mountain National Park with the Osprey Exos 48  our Best Buy winner.
We hiked high and low, from the Continental Divide to the Appalachian Trail, to find the best ultralight backpacks! Here, our lead tester, Brandon, celebrates another beautiful day in Rocky Mountain National Park with the Osprey Exos 48, our Best Buy winner.

Jane Jackson & Brandon Lampley