The world's most in-depth and scientific reviews of gear

Garmin Forerunner 45S Review

An affordable GPS watch with a few great features and accurate tracking
Best Buy Award
  • 1
  • 2
  • 3
  • 4
  • 5
Price:  $200 List | $194.95 at Amazon
Compare prices at 2 resellers
Pros:  Inexpensive, good for petite wrists, easy to use, downloadable workouts
Cons:  Plastic, limited sport profiles with specific metrics
Manufacturer:   Garmin
By Larin McPeak ⋅ Review Editor  ⋅  Nov 26, 2019
  • Share this article:
Our Editors independently research, test, and rate the best products. We only make money if you purchase a product through our links, and we never accept free products from manufacturers. Learn more

#6 of 9
  • Features - 35% 6
  • Ease of Use - 25% 8
  • Battery Life - 15% 6
  • Accuracy - 15% 7
  • Design - 5% 6
  • Ease of Set-up - 5% 8

Our Verdict

The Garmin Forerunner 45s is a great little watch for runners with smaller wrists that want GPS accuracy for their runs and a simple user interface. Not only is it very comfortable to wear, but it also provides a long list of new features and data tracking compared to its predecessor, the Garmin Forerunner 35, but managed to keep it all at a very affordable price. If you are looking for a running GPS watch, this might be the watch for you. Should you need a watch that tracks other sports, there might be another more suitable watch available that provides more multi-sport metrics and data.

Compare to Similar Products

Our Analysis and Test Results

Garmin has done an excellent job with the Forerunner 45s. Many runners, especially petite ones, are tired of wearing heavy, bulky watches in order to get their running metrics or an acceptable battery life. The Forerunner 45s offers an extensive list of features and metrics, plus a decent battery life, without creating a brick on your wrist. For runners not looking to be burdened with a complicated menu or a bulky watch, the Garmin Forerunner 45s really packs a lot into a small package, and that is why it won our Best Bang for the Buck Award.

Performance Comparison

The fit on tiny wrists was great and the 3 data fields are very easy to view during runs.
The fit on tiny wrists was great and the 3 data fields are very easy to view during runs.


The Forerunner 45s has all the basics that have become standard on a GPS watch, namely, GPS tracking, a step counter, optical heart rate monitor, an accelerometer (measures speed and distance), smart notifications and a calorie counter. This time, Garmin has packed some goodies into this little package that we did not expect in such an affordable watch.

It also has sleep monitoring, incident detection (notifies your emergency contact if you have an accident), VO2 max, LiveTrack (so your selected contacts can track your runs), and, what is our most favorite Garmin addition, downloadable structured workouts!

What these "extras" have resulted in is a watch that can not only accompany you through the start of your running career, but also carry you through to beginner ultra marathon distances. The fact that Garmin added the downloadable structured workouts to such an affordable watch is really amazing. For serious athletes that stick to a set training plan, this function is a godsend.

Basically, in conjunction with the Garmin Connect online platform or even in the app, your coach, or you, can build specific workouts and download them to the Forerunner 45s. As an example, if your coach wants you to do a one hour block with fartleks of 2 minutes every 20 minutes, he can put this into Garmin Connect, sync the watch, and start the workout. Instead of having to constantly look at the watch to see the time, the watch will beep and/or vibrate (however you programmed it) to let you know: SPRINT! And when the hour is up, the watch will also alert you. This feature alone makes serious training programs so much easier because you can just focus on your run and not on time. Even some more expensive watches on the market do not offer this type of customization.

Garmin also included a cool feature that no other company has at the moment called, "Move IQ." This feature is what we consider to be "the commuters feature." If you walk or cycle to work, for example, you may not want this calculated as an activity since there might be lots of red lights, stop and go, etc. This is your means of transit, and you won't want it affecting your performance data overall in Garmin, but you may want it tracked to see how long your commute lasted. This is where the Move IQ comes in.

The Forerunner 45s also monitors your VO2 Max. This is a metric used by athletes to determine their cardiovascular fitness level. Specifically, it measures how well you can bring oxygen in and transport it to your muscles and then use it to produce energy. The higher the number, the more fit you are. The watch calculates this by accumulating data from your activities where your heart rate is elevated to at least 70% of your max.

The 45s is much smaller than the feature-packed Apex (right).
The 45s is much smaller than the feature-packed Apex (right).

Ease of Use

Usually, a more budget-friendly watch results in fewer features, which automatically results in a device that is easier to use. There are fewer features to scroll through the menus, the app has less data recorded, and the displayed information is usually reduced.The Forerunner 45s is not about less though. This watch has maintained an excellent palate of features but managed to balance that with an easy to use platform. Scrolling through the menus is easy and the button layout is clear, as well as labeled.

Because the Garmin Forerunner 45s is a smaller watch, the buttons are smaller than many competitors.

Syncing to the app or the online platform, Garmin Connect also proved to function smoothly. This also enabled the weather data, smart notifications, calendar, etc., to sync onto the watch without errors.

Battery Life

Because of its small size, the battery is also necessarily smaller, and unfortunately, the "normal usage" battery life was rather disappointing. Although Garmin advertises that the daily usage (they call it "smartwatch mode") should be up to 7 days, we never got more than four days, even if we were not exercising during that time period.

Garmin also advertises that their GPS mode will last up to 13 hours, but we only got up to about 10 hours in the run activity.

We wondered if the upgrade to a color screen on such a small watch with a small battery played a roll in the short "smartwatch mode" battery life because the predecessor to the 45s, which had only a black and white screen, had an amazingly long "smartwatch mode" battery life. That said, it was missing many of the best features of the Forerunner 45s.

The charger is suitable to be used simultaneously during an activity. This means that if you are doing a longer endurance event than the battery can survive, then you can connect it to an external portable battery and place it in your running vest and the watch activity will not be disrupted while the watch is charging. This ability enables the watch to last even the longest ultras, as long as the external battery still has a charge.

GPS signal can oftentimes be blocked by tall structures. We did not have this issue with our reviewed watches this time.
GPS signal can oftentimes be blocked by tall structures. We did not have this issue with our reviewed watches this time.


Although this watch is considered a "budget watch," we were fairly blown away by its accuracy of both the GPS and the optical heart rate monitor.

In our testing, the Forerunner 45s reported less than a 2% difference in ran distance (mileage covered during activity) when compared to other watches or google maps. This difference was not much more than more expensive watches.

The optical heart rate monitor reported heart rate differences of less than 1.5% against the heart rate measurements of the chest belt and more expensive watches. This is by far the best performance that any GPS watch in our "budget" category has ever completed! Frankly, we were all shocked at how accurately the 45s performed.


The Forerunner 45s design is not the best-looking watch. It is plastic and definitely looks like a more affordable GPS sports watch. The screen resolution is quite low, and we wondered why Garmin bothered upgrading to a color screen because the resolution isn't there to make it feel like an upgrade. Though we never had problems reading the screen, it just seemed superfluous.

One huge positive that this watch has is its size. Petite people do not always like big watches, and this gives them an option that still offers a complete runner's portfolio of features. On our smaller testers, this watch was by far the most fitting and comfortable. It also comes in some fun colors, which gives you some personalization options that many watches do not.

Ease of Set-Up

The Forerunner 45s was fairly easy to set up. We were able to accomplish this with a simple app download, sync, addition of a few details to our weight, age, gender, etc. and we were up and running. The syncing never had errors, although occasionally, the app itself was slow to open. We think this is because the Garmin Connect platform, both app and online, is one of the most robust in the GPS watch world. It stores and analyzes more data than any other competitor.

All in all, we did not require any instructions to set up this watch as it was all clear and/ or intuitive, and if you are already in the "Garmin world," then the set up will be even less time consuming than if you are just starting with Garmin.

When connected to a phone  the Garmin has a screen that shows your daily calendar.
When connected to a phone, the Garmin has a screen that shows your daily calendar.


The 45s wins our Best Bang for the Buck award hands down. Garmin has packed a lot of features into a small package and made it all for an affordable price. This is a versatile little watch that can expand its mission as you expand your distances.


If you need a GPS watch for running that doesn't break the bank but still has some great features and tracking abilities, then the Forerunner 45s is perfect for you. Probably better fitting for petite people, but still ready for action for larger runners too, the 45s easily covers your running needs without emptying your pocketbook.

Larin McPeak