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Garmin Forerunner 45 vs 55 (2022): Which Smartwatch Should You Get?

Runners have long relied on Garmin’s Forerunner series to track their runs. The Garmin Forerunner 45 and 55 are good entry-level models for those on a budget. The Forerunner 55 is the direct upgrade to the 45, a follow-up two years in the making. It promises better battery life, additional features, and a much-awaited design update, too. Given these changes, how does the Forerunner 45 fare? Below, we compare the two GPS running watches to find out.

Garmin 45 vs 55 Comparison Chart

ModelGarmin Forerunner 45Garmin Forerunner 55
Sizes39mm, 42mm42mm
DisplayTransflective memory-in-pixel color displayTransflective memory-in-pixel color display
Display Size1.04 in.1.04 in.
LensChemically strengthened glassChemically strengthened glass
StrapSiliconeSilicone quick-release bands
Battery LifeSmartwatch mode: Up to 7 days
GPS mode: 13 hours
Smartwatch mode: Up to 2 weeks
GPS mode: 20 hours
Water Rating5 ATM5 ATM
Key SensorsGPS, GLONASS, GALILEO, heart rate monitor, accelerometerGPS, GLONASS, GALILEO, heart rate monitor, accelerometer
Smart NotificationsYesYes
Incident DetectionYes (requires smartphone)Yes
Heart Rate MonitoringYesYes
Respiration RateNoYes
Sleep TrackingYesYes
PacePro Pacing StrategiesNoYes
Pool Swimming ProfileNoYes
ConnectivityBluetooth, ANT+Bluetooth, ANT+


Unlike the Forerunner 45, the Forerunner 55 now supports quick-release bands and comes only in one size model.

Garmin Forerunner 45 vs 55 Design comparison
Notice the wedge on the Forerunner 55 (right) for the quick release bands missing on the Forerunner 45 (left)

Placed side by side, it’s hard to tell the difference between the Garmin Forerunner 45 and 55. But perhaps the most noticeable change can be seen above and below the case. A small protrusion now indicates the Forerunner 55 is compatible with 20mm quick release bands. This makes it easier to swap straps and change the aesthetic of your wearable.

Other than the band mechanism, you’re getting the same Forerunner 45 form factor on the 55. The strap is still made from silicone. For the lens, chemically strengthened glass remains the norm. You still have five buttons โ€” three on the left, two on the right โ€” including a dedicated button for the activity timer. As a whole, the watch is still water-resistant up to 5 ATMs.

The 45, however, comes in two sizes โ€” 39mm (originally labeled 4S) and 42mm. The 55, on the other hand, is available only in 42mm. It’s also ever so slightly thicker than the 42mm size of the Forerunner 45.

Because there’s no considerable bump in design and dimensions, you’re getting the same 1.04-inch color display on the 55. Like the 45, the display is not a touchscreen. Instead, the physical buttons serve as your navigation tools.

Fitness and Activity Tracking

Garmin’s Forerunner 55 has better running features and support for non-running workouts.

Garmin Forerunner 45 vs 55 fitness features
Cardio profile on the Forerunner 45 (left); a list of the workouts on the Forerunner 55 (right)

At their core, the Garmin Forerunner 45 and 55 are running watches. Both provide GPS-based distance, time, and pace. They also monitor your cadence and are foot pod capable. On the Forerunner 45, running profiles are limited to standard and treadmill runs. However, you can add indoor track running through the app.

On the Forerunner 55, you get more running profiles onboard. Aside from regular runs, it supports outdoor track, treadmill, indoor track, and virtual running. It also comes with the PacePro Pacing Strategies function. This feature provides an in-depth insight into your pace, including variables such as altitude and physical conditions.

Outside running, the wearables are modest fitness trackers. You can track daily metrics like steps, calories burned, and distance. There’s also access to comprehensive training and planning metrics. However, you will get more gym activity profiles on the 55 than on the 45. It also comes with outdoor recreation, kid activity-tracking features, and a pool swimming profile.

Health and Safety Features

The Garmin Forerunner 55 has a few more health features than the Forerunner 45.

Garmin Forerunner 45 vs 55 health features
Quickly view health stats and stress levels with these Garmin wearables

As for health features, these Garmin wearables are quite modest. There’s no ECG here or SpO2 monitoring, unlike their flagship counterparts and rivals. Instead, the Forerunner 45 and 55 focus on the basics. You have 24/7 heart rate tracking with abnormal heart rate alerts. There’s also advanced sleep tracking and all-day stress monitoring.

Garmin exclusives like Fitness Age and Body Battery are present in the two. Fitness Age estimates how fit you are compared to your age, while Body Battery assesses your energy levels to tell you if you should exercise or prioritize recovery. For the Forerunner 45, however, the Fitness Age feature is in-app only.

The Forerunner 55 also adds a few more tools. For instance, the wearable can measure respiration rate. It also offers relaxation and hydration reminders. Female users stand to benefit from the women’s health function, too. As for safety features, the 55 offers no changes from the 45. It still comes with livetrack and incident detection like its predecessor.

Smart Features and Battery Life

While there are no changes in smart features, the Forerunner 55 offers significant battery life improvement over the Forerunner 45.

Garmin Forerunner 45 vs 55 smart features
Both watches support call, text, and app notifications (left) and offer music controls

Compared to other wearables, the smart features of the Forerunner 45 and 55 are basic. For instance, you have your usual smart notifications, although you can’t take calls. The watches come with weather and calendar apps and find my phone/watch functionality is also present. 

To personalize the devices, downloadable watch faces, widgets, and apps are available from Connect IQ. As expected, these running watches can control smartphone music, too.

As for battery life, the battle between the Garmin 55 vs 45 is lopsided. The latest iteration is rated to have up to two weeks of battery life in smartwatch mode. With GPS on, the Forerunner 55 should still give you 20 hours of use. These numbers are upgrades from the 45’s one-week battery life in smartwatch mode and 13 hours in GPS mode.


The Garmin Forerunner 55 offers enough upgrades to make it a compelling purchase over the Forerunner 45.

The follow-up to the Forerunner 45 may have been a long time coming but it doesn’t disappoint. With the Forerunner 55, Garmin maintains a no-fuss running watch but with modest and practical upgrades. These changes include additional running profiles, extra health tools, and easy-to-swap straps. Battery life also sees a significant improvement. And with more workouts supported, you’re getting a more versatile wearable, too.


๐Ÿ“Œ What’s the key difference between the Garmin Forerunner 45 and 55?

Garmin’s Forerunner 55 only comes in one size, compared to the two size models of the 45. It also offers more workout profiles and better battery life.

๐Ÿ“Œ Does the Garmin Forerunner 55 support contactless payment?

No, the Forerunner 55 does not have Garmin Pay.

๐Ÿ“Œ How much data is stored in the Garmin Forerunner 45?

The Forerunner 45 can store up to 80 hours of activity data.

๐Ÿ“Œ Is live event sharing available in the Garmin Forerunner 55?

Yes, live event sharing is available on the Forerunner 55. However, the feature is limited to Android phones only.

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Mari Bassig

Senior Editor, writer and researcher passionate about gadgets, social media, and music.