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Garmin Forerunner 645 vs 935 vs 945 – What’s the Difference?

garmin forerunner 645 vs 935 vs 945 compared
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Featured in this comparison, is the newly released Forerunner 945, the older Forerunner 935 and the relatively new Forerunner 645 – Three of the best smartwatches from Garmin, all fitness focused and among the best for comprehensive fitness tracking. These three share a lot of features in common with some few differences. We compare the Forerunner 645 vs 935 vs 945 specs and features so you know what the differences are and which is the best choice for you.

Garmin Forerunner 645 vs 935 vs 945 – Specifications

Garmin Forerunner 645 MusicGarmin Forerunner 935Garmin Forerunner 945
garmin forerunner 645 specsgarmin forerunner 935 specsgarmin forerunner 945 specs


Device nameGarmin Forerunner 645 MusicGarmin Forerunner 935Garmin Forerunner 945
Device typeFitness/GPS smartwatchFitness/GPS smartwatchFitness/GPS smartwatch
Predessesor____Garmin Forerunner 935
Successor--Garmin Forerunner 945Garmin Forerunner 955
Released dateApril, 2018March, 2017April, 2019
Ideal forUnisexMenMen


Display typeTransflective memory-in-display (MIP)Transflective memory-in-display (MIP)Transflective memory-in-display (MIP)
Display size1.2 inch1.2 inch1.2 inch
Display resolution240 x 240 pixels240 x 240 pixels240 x 240 pixels
Pixel density282.8 PPI282.8 PPI282.8 PPI
Input type 5 buttons, (Not touchscreen)5 buttons (Not touchscreen)5 buttons (Not touchscreen)
Customizable watch faceYesYesYes


Dimension42.5 x 42.5 x 13.5 mm47 x 47 x 13.9 mm47 x 47 x 13.7 mm
Weight42.2 grams49 grams50 grams
Casing materialFiber-reinforced polymerFiber-reinforced polymer with polymer rear coverFiber-reinforced polymer with polymer rear cover
Strap/band materialSiliconeSiliconeSilicone
Bezel MaterialStainless steelFiber-reinforced polymerFiber-reinforced polymer
Strap size20mm22mm22mm
Interchangeable band Yes, 20mmYes, 22mmYes, 22mm
Screen protectionCorning Gorilla Glass 3Chemically strengthened glassCorning Gorilla Glass DX
Water resistant/ProtectionYes, 5ATMYes, 5ATMYes, 5ATM
Swim-proofYes, recommendedYes, recommendedYes, recommended


Internal storage4GB64MB16GB
Memory card slotNoNoNo


BluetoothYes, and ANT+Yes, and ANT+Yes, and ANT+
Bluetooth callingNoNoNo
Payment systemGarmin PayNoGarmin pay




Email alertYesYesYes
SMS alertYesYesYes
Calls alertYesYesYes
Event reminderYesYesYes
Third-party appsYesYesYes
Text responseYes (android only)NoYes (android only)


Sleep apneaNoNoNo
Sleep trackingYesYesYes
Floors climbedYesYesYes
Heart rate monitoringYesYesYes
VO2 Max.YesYesYes
Blood oxygenNoNoYes
Blood pressureNoNoNo
Menstrual cycle trackingYesYesYes
Swim trackingYesYesYes
Under-water heart rate trackingNoNoYes
Preloaded mapsNoYesYes
On-screen workout modesNoNoNo
Triathlon modeYesYesYes
ECG TrackingNoNoNo
Preloaded sport modesYesYesYes
Safety trackingYesYesYes


Music streamingYesYesYes
Bluetooth musicYesYesYes



Operating system (OS)Proprietary OSProprietary OSProprietary OS


Type of batteryNon-removable Li-ion batteryNon-removable Li-ion batteryNon-removable Li-ion battery
Battery capacity ------
Battery lifeSmartwatch Mode: Up to 7 days
GPS mode with music: Up to 5 hours
GPS mode without music: Up to 14 hours
Smartwatch Mode: Up to 2 weeks
GPS mode with music: Up to 10 hours
GPS mode without music: Up to 36 hours
Smartwatch Mode: Up to 2 weeks
GPS mode with music: Up to 10 hours
GPS mode without music: Up to 36 hours
Charging typeUSB charging cableUSB charging cableUSB charging cable
Charging timeAbout 1-2 hoursAbout 1-2 hoursAbout 1-2 hours
Battery saver modeNoNoYes
Solar powerNoNoNo
Rapid chargingNoNoNo




Control cameraYesYesYes
Music controlYesYesYes
Find phoneYesYesYes


Compatibility Android and iOS
Check if your device is compatible
Android and iOS
Check if your device is compatible
Android and iOS
Check if your device is compatible
Companion appGarmin connect IQGarmin connect IQGarmin connect IQ
Voice commandNoNoNo


Garmin Forerunner 645 MusicGarmin Forerunner 935Garmin Forerunner 945
USB charging cableUSB charging cableUSB charging cable
Quick start guideQuick start guideQuick start guide
NOTE: We can't guarantee that all the information on this table are 100% correct. Read full disclaimer. Please, report an error.
Official SiteOfficial SiteOfficial Site

Garmin Forerunner 645 vs 935 vs 945 – The Difference?

Features compared
  • Design
  • All three devices look decent and stylish in their respective ways. However, we have a Forerunner 645 with a smaller case size compared to the other two which are quite bulky. The 645 is also a bit slimmer than the 945 and 935 and has a smaller 20mm straps size as compared to 22mm on the 935 and 945 which clearly suggests that the Forerunner 645 as a great choice for women while the 945 and 935 will suit men better.

    The stainless steel bezel of the 645 also gives it the classic appearance that makes it a nice fit for official outings, but the finely crafted bezel of the 945 with the stylish markings is quite more commanding and outstanding.

    As per durability, the 945 and 645 both have Corning Gorilla glass manning the screens which are more durable than the undisclosed chemical-strengthened glass of the 935 which means the 645 and 945 can well do with some knocks and still work fine (Better choices for adventure).

  • Connectivity
  • The Forerunner 645 and 945 joins the list of Garmin’s smartwatches with NFC that supports Garmin Pay – a contactless payment system that allows you to make payment on the go from these two. Unlike the 935 which doesn’t have NFC.

  • Fitness Tracking
  • As per fitness tracking, these three remain some of the best choices for fitness tracking. Each is packed with all the standard sensors you’d find in other high-end fitness smartwatches.

    However, the new 945 comes with a Pulse Ox sensor that will be able to monitor blood oxygen level which is very insightful during acclimation activity helping you see how your body is adjusting to higher levels.

    The Forerunner 945 also features the Garmin Coach which provides guidance and free adaptable training plans that suit your training style. You can as well create your own custom workout modes.

    Also lacking on the 645 and 935, but available on the 945 is the full-color topography map feature that’s also available on the Fenix 5X Plus. The full-color map helps you navigate your way through even difficult terrains.

  • Media
  • While the Forerunner 645 and 945 allow you to store your music on the watch which you can enjoy on the go, the 935 lacks that feature. Moreover, the Forerunner 945 has a higher onboard storage than the 645 as it can take up to 1000 tracks as against 500 on the 645.

  • Battery Life

Each of these three has a remarkable battery life that lasts long enough to see you through a couple of days. However, the 935 and 945 have slightly longer battery life than the 645.

While you get about 10 days on regular usage with 935 or 945, you will get less than that with the 645, about 6 days which is still impressive.

Which is the Best?

From the features and design, all three devices are great choices for comprehensive fitness tracking and have decent appearances. However, Forerunner 645 and 945 have more features than the 935 with the 945 having the most features with respect to the presence of Pulse Ox and full-color map which aren’t present on the other two.

Obviously, the Forerunner 945 is the best choice, it’s the most comprehensive with more features, and as well, the spectacular compact design and the long battery life make it such a great bargain even at $600. A great choice for men, professional runners and other athletes alike.

On the other hand, Forerunner 645 also spots a decent appearance with a rich list of features which certainly makes it a better choice over the 935 and going by the sizes, the 645 is a great choice for women.

The Forerunner 935 cost almost about the same price as the 645, although it lacks a few features, but has longer battery life. It’s a nice alternative to the 945 which is somewhat pricey, but that justifies the more features.

Here is a summary;

Garmin Forerunner 945 The best choice, a more comprehensive fitness tracker with an impressively long battery life. A great choice for men.
Garmin Forerunner 645A comprehensive fitness smartwatch, a great choice for women.
Garmin Forerunner 935A nice alternative to the 945 with long battery life.

Our Pick

The Garmin Forerunner 945 is a more comprehensive choice with more features and an outstanding design that makes it such a great choice in the gym and off the gym. It’s our preferred choice.