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Garmin 645 vs 245 (2021): Which Forerunner Running Watch Should You Get?

Garmin’s Forerunner series are among the most popular running watches available today. With five different models in the more recent 45 series, deciding which to get can be a bit tricky. Below we compare two highly rated GPS running smartwatches in the lineup: the Garmin Forerunner 645 and the Garmin Forerunner 245. Both have their own exclusive features, making one or the other the better-suited watch for you.

Garmin 645 vs 245 Running Watch Comparison Chart

ModelGarmin Forerunner 645Garmin Forerunner 245
Garmin 010-01863-00 Forerunner 645, GPS Running Watch with Pay Contactless Payments and Wrist-Based...Garmin Forerunner 245, GPS Running Smartwatch with Advanced Dynamics, Slate Gray
PriceCheck PriceCheck Price
Dimensions42.5 x 42.5 x 13.5 mm42.3 x 42.3 x 12.2 mm
Display1.2″ diameter1.2″ diameter
Resolution240 x 240 pixels240 x 240 pixels
LensCorning Gorilla Glass 3Corning Gorilla Glass 3
BezelStainless steelFiber-reinforced polymer
Weight41.8 g38.5 g
Water Rating5 ATM5 ATM
Memory200 hours of activity data200 hours of activity data
Outdoor Recreation ProfilesYesNo
Heart Rate MonitorYesYes
Pulse OximeterNoYes
Body Battery Energy MonitorNoYes
All Day Health TrackingYesYes
Stress TrackingYesYes
Barometric AltimeterYesNo
Incident DetectionYesYes
Battery LifeGPS On: 14 hours
GPS Off: 7 days
GPS On: 24 hours
GPS Off: 7 days


The Garmin Forerunner 645 has a more premium build than the 245.

The bezels of the Garmin Forerunner 645 (left) and 245 (right) are their most noticeable design difference.

Garmin Forerunner 645 and 245 running watches can be easily told apart through their bezels. The 645 sports a stainless steel bezel giving it that sleeker, premium look while the 245 uses a fiber-reinforced polymer instead. The mostly plastic build of the Forerunner 245 allows it to be offered at a lower price range than the 645, among other things.

Note that, while different colors are available for both GPS watches, all of them look predominantly the same, and only the 245 shows hints of color on the actual device. You’ll notice that there are small violet accents on the image of the Berry variant of the 245 above.

Size-wise, the Garmin 645 and 245 watches are very close in overall dimensions and weight. They also have similar 1.2-inch display sizes with resolutions of 240 x 240 pixels. They have water ratings of 5 ATM, allowing full use for swimming or kayaking. Finally, they also have similar buttons and placements as other Forerunner 45 series watches.

Health and Activity Tracking

The Garmin Forerunner 645 has more exercise modes while the 245 has more health sensors.

The Garmin 645 watch has several more outdoor exercise profiles than the 245.

If you enjoy outdoor recreation, the Garmin Forerunner 645 will likely be a better fit for you thanks to its extra profiles for those activities. You can select and track rowing, paddle-boarding, snowboarding, skiing, and XC skiing as well as determine your vertical speed and total descent/ascent with the Garmin 645. These have all been taken out with the Forerunner 245.

However, Garmin did give the 245 more health-related features, such as a pulse oximeter that measures your blood oxygen levels. It combines well with the heart rate monitor for a more accurate analysis of your fitness and sleep data. Moreover, the Garmin 245 has the Body Battery energy monitor, which can help you find the best times to train and rest depending on your energy levels throughout the day.

Both Garmin Forerunner watches have wrist-based heart monitoring, step and intensity minutes counters, calories burned and sleep tracking, and female health tracking. They also share the same gym, run and swim activity profiles. You can get free training plans and guidance from Garmin Coach, plus there are more metrics and features to take advantage of, such as VO2 max, training load, training effect, running dynamics, etc.

Smart Features

The Garmin Forerunner 645 has better connectivity and more tools than the 245.

With its extra sensors, the Garmin Forerunner 645 makes for a better outdoor training watch.

The key advantage of the Forerunner 645 over the 245 for outdoor recreation and training is its extra sensors. The 645 has a barometric altimeter, gyroscope, and thermometer in addition to all of the sensors its shares with the 245. The altimeter tracks changes in pressure to compute vertical movements for accurate tracking while trail running, climbing, and cycling. It also enables Running Power data, though an additional chest strap or Running Pod is required.

While both utilize GPS, GLONASS, and GALILEO for accurate mapping and navigation, the Garmin 645 also has more connectivity options than the 245, such as Wi-Fi and NFC. This means you can use your 645 with Garmin Pay to make contactless payments at establishments with supported readers.

Like most Garmin smartwatches, you can receive notifications from your phone after pairing them, which is as easy as holding the Light button. The Connect IQ store lets you download watch faces, apps, and widgets to customize your device further. Both 645 and 245 watches also have incident detection and assistance features that let you send your location to your emergency contacts.

Finally, there are Music variants for both Garmin Forerunner 645 and 245, allowing you to download up to 500 songs to the device as well as connect Bluetooth headphones. They cost about $50 more than the standard models but are worth it if you want to have music on your smartwatch and not depend on playing songs from your smartphone.

Battery Life

The Garmin Forerunner 245 has a better battery life than the 645.

You can get more GPS usage out of the Forerunner 245.

Garmin improved the battery life of the Forerunner 245, as it can last up to 24 hours with the GPS turned on. This is more impressive than the 645’s 14 hours in GPS mode, which is unfortunate for a watch that seems particularly well-suited for outdoor use where GPS is critical.

With GPS switched off, both 645 and 245 can run up to 7 days without recharging, so you can wear them all day and track your sleep at night without worrying about your watch dying out on you quickly.


The Garmin Forerunner 645 is recommended for outdoor use while the Forerunner 245 is better otherwise.

With its extra sensors and outdoor activity profiles, the Garmin Forerunner 645 GPS running watch is better equipped for training and recreation out in the wilds. If you enjoy more rigorous adventures than running and cycling, you’re likely going to more fully utilize the 645’s features. Plus, it has a more premium stainless steel finish and you can pay with it instead of reaching for your wallet. Moreover, you can look forward to significant discounts for it now that newer models in the 45 series are out.

If you’re not keen on the added features of the 645, the Garmin Forerunner 245 GPS running watch arguably offers better value, as its retail price is about $100 less and its battery life is considerably improved. You’ll also get more accurate health tracking thanks to its pulse ox and Body Battery features while still getting adequate connectivity.


📌 Is Garmin 245 worth it?

Yes, the Garmin Forerunner 245 gives serious runners better training features, activity tracking, and battery life than most other smartwatches at its price range.

📌 Does Garmin 645 have Body Battery?

No, the Garmin Forerunner 645 does not have the Body Battery energy monitor feature. It is available on the Forerunner 245, however.

📌 Does Garmin 245 track swimming?

Yes, you can use the Garmin Forerunner 245 for indoor swimming training, tracking your heart rate as well as laps, stroke counts, swim intervals, etc. However, open water swims or deep dives are not supported.

📌 Does Garmin 245 play music?

The Garmin Forerunner 245 comes in Standard and Music versions. For around $50 more, the Forerunner 245 Music includes music storage and Wi-Fi connectivity to allow you to download and play up to 500 songs directly from the watch.

Last update on 2021-06-13 / Affiliate links / Images from Amazon Product Advertising API

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Derick Bondoc

Managing Editor at Compare Before Buying. Writer and researcher passionate about gadgets, gaming and snacks.