Last Updated on March 28, 2020 by Jude Simeone

Garmin Forerunner 645 Full Specifications – The Forerunner 645 is a nice GPS smartwatch housed in a classic design and hosts a lot of features that include onboard music storage, NFC that supports Garmin Pay with Wi-Fi also available.

The Forerunner 645 comes in two versions; the standard 645 and 645 music. The difference between these two is the presence of significant storage space on the later which allows you to take your favorite tracks along with you. The Forerunner 645 like other Garmin smartwatches also has an impressive battery life.

Garmin Forerunner 645/645 Music Full Specifications

	Garmin Forerunner 645	Garmin Forerunner 645 Music
EDITOR'S RATING	Design: (4.1 / 5) Battery: (4.1 / 5) Fitness tracking: (4.5 / 5) Features: (4.0 / 5) Price: (3.4 / 5) Average: (4.0 / 5)	Design: (4.0 / 5) Battery: (4.1 / 5) Fitness tracking: (4.7 / 5) Features: (3.5 / 5) Price: (3.9 / 5) Average: (4.0 / 5)
WHERE TO BUY	Check @ Amazon	Check @ Amazon
ABOUT DEVICE
Device name	Garmin Forerunner 645	Garmin Forerunner 645 Music
Device type	Fitness/GPS smartwatch	Fitness/GPS smartwatch
Predessesor	__	__
Successor	--	--
Released date	April, 2018	April, 2018
Ideal for	Unisex	Unisex
DISPLAY
Display type	Transflective memory-in-display (MIP)	Transflective memory-in-display (MIP)
Display size	1.2 inch	1.2 inch
Display resolution	240 x 240 pixels	240 x 240 pixels
Pixel density	--	--
Input type	5 buttons, (not touchscreen)	5 buttons, (not touchscreen)
Always-on	Yes	Yes
BODY
Shape	Circular	Circular
Dimension	42.5 x 42.5 x 13.5 mm	42.5 x 42.5 x 13.5 mm
Weight	41.8 grams	42.2 grams
Casing material	Fiber-reinforced polymer	Fiber-reinforced polymer
Strap/band material	Silicone	Silicone
Bezel Material	Stainless steel	Stainless steel
Strap size	20mm	20mm
Screen protection	Corning Gorilla Glass 3	Corning Gorilla Glass 3
Water resistant/Protection	Yes, 5ATM	Yes, 5ATM
Swim-proof	Yes, recommended	Yes, recommended
Color(s)	Black	Black
MEMORY
RAM	--	--
Internal storage	__	4GB
Memory card slot	No	No
CONNECTIVITY
Bluetooth	Yes, and ANT+	Yes, and ANT+
Bluetooth calling	No	No
Wi-Fi	Yes	Yes
NFC	Yes	Yes
GPS	GPS/GLONASS/Galileo	GPS/GLONASS/Galileo
CELLULAR TECHNOLOGY
Technology	No	No
SIM	No	No
Band	No	No
NOTIFICATIONS
Email alert	Yes	Yes
SMS alert	Yes	Yes
Calls alert	Yes	Yes
Event reminder	Yes	Yes
Weather	Yes	Yes
Third-party apps	Yes	Yes
FITNESS TRACKING
Sleep apnea	No	No
Sleep tracking	Yes	Yes
Steps	Yes	Yes
Floors climbed	Yes	Yes
Heart rate monitoring	Yes	Yes
Calories	Yes	Yes
Distance	Yes	Yes
Stress	Yes	Yes
VO2 Max.	Yes	Yes
Blood oxygen	No	No
Blood pressure	No	No
Menstrual cycle tracking	Yes	Yes
Swim tracking	Yes	Yes
Under-water heart rate tracking	No	No
Preloaded maps	No	No
On-screen workout modes	No	No
Triathlon mode	Yes	Yes
ECG Tracking	No	No
Preloaded sport modes	Yes	Yes
Safety tracking	Yes	Yes
MEDIA
Audio	No	mp3/mp4
Music streaming	No	Yes
Bluetooth music	No	Yes
Radio	No	No
Loudspeaker	No	No
Microphone	No	No
Camera	No	No
SENSORS
Accelerometer	Yes	Yes
Barometer/Altimeter	Yes	Yes
Heart rate monitor (HRM)	Yes	Yes
Compass	Yes	Yes
Gyroscope	Yes	Yes
Ambient light	__	__
Pulse Oximeter	No	No
ECG	No	No
Thermometer	Yes	Yes
Other sensors	--	--
PLATFORM
Operating system (OS)	Proprietary OS	Proprietary OS
Chipset	--	--
CPU	--	--
GPU	--	--
BATTERY
Type of battery	Non-removable Li-ion battery	Non-removable Li-ion battery
Battery capacity	--	--
Battery life	Smartwatch Mode: Up to 7 days GPS mode: Up to 14 hours	Smartwatch Mode: Up to 7 days GPS mode with music: Up to 5 hours GPS mode without music: Up to 14 hours
Charging type	USB charging cable	USB charging cable
Charging time	About 1-2 hours	About 1-2 hours
Battery saver mode	No	No
Solar power	No	No
Rapid charging	No	No
CLOCK FEATURES
Time/Date	Yes	Yes
Stopwatch	Yes	Yes
Alarm	Yes	Yes
OTHER FUNCTIONS
Control camera	Yes	Yes
Music control	Yes	Yes
Find phone	Yes	Yes
Text response	Yes (android only)	Yes (android only)
MISC
Payment system	Garmin Pay	Garmin Pay
Compatibility	Android and iOS Check if your device is compatible	Android and iOS Check if your device is compatible
Companion app	Garmin connect IQ store	Garmin connect IQ store
Customizable watch face	Yes	Yes
Interchangeable band	Yes, 20mm	Yes, 20mm
Voice command	No	No
BOX CONTENTS
	Garmin Forerunner 645	Garmin Forerunner 645 Music
	Straps	Straps
	USB charging cable	USB charging cable
	Quick start guide	Quick 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 Site	Official Site

Garmin Forerunner 645/645

1. Design

The Forerunner 645 is housed in a decent circular shape made of some of the most durable materials. It has a stainless steel bezel that does make it look classic and decent enough to grace your wrist even for high profile occasions.

The sunlight visible transflective Memory-in-pixel display is not the most interactive display, but it’s certainly a lot easier to view outdoors. Something, those who engage in outdoor sport will appreciate especially when in the heat of the sun.

The sizes are moderate too which means this is one watch that will be a nice fit for a lot of people, while the watch face is customizable. Just in case you don’t like it, you can simple download one of your choice from the Garmin connect store where they have some really nice watch faces.

2. Long Battery Life

One nice attribute of the Forerunner 645 is the quite impressive battery life that will see you go longer on a single charge with this device. On smartwatch mode, it’s about 4-7 days long battery life while with GPS active, you should expect about 10 hours of battery life.

No doubt impressive, and a great deal for runners who engage in longer durational activities.

3. Waterproof Rating

The Forerunner 645 is rated 5ATM which means it water-resistant up to 50 meters. So it’s swim-proof and with the swim-tracking features such as stroke count, pace, calories and swim efficiency (SWOLF), it’s a great choice for swimmers who like to monitor their performance while swimming.

4. Activity/Fitness Tracking

As a fitness smartwatch, the Forerunner 645 comes with all the standard sensors you’d expect to find in a fitness tracker.

It includes the heart rate monitor, inbuilt GPS with support for the multi-satellite system, altimeter, and accelerometer which accounts for the 645 huge fitness tracking features and support for automatic tracking of a number of sport modes.

5. Media

The Forerunner 645 and 645 Music are the two models released under the 645 series. While the standard 645 model lacks onboard music storage, the 645 Music has enough onboard storage to contain over 500 music tracks.

You can download and as well stream your favorite tracks from Spotify to the 645 which you can listen to on the go via a Bluetooth enabled earbud.

This is one nice feature that comes handy in helping stay remain on focus, avoiding unnecessary distractions.

6. Notifications

With Wi-Fi and Bluetooth available, the Forerunner 645 is able to keep you connected to all that matters to you. It’s compatible with both Android and iOS devices which when successfully connected to a compatible device, syncs emails, incoming calls and other notifications alerts from both third-party and native applications to the watch.

The Forerunner 645 also features an NFC that supports Garmin Pay which lets you make payment directly from the watch.

Pros

Cons

Jude Simeone

Hi! I’m Jude, the creator and chief editor at Smartwatchseries.com

I’m a scientist, a 3D artist, and a passionate fitness enthusiast. On here, I and other smartwatch fans work hard to help you find the right smartwatch for you with our guides, reviews, and comparisons.

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