Garmin Forerunner 645 running watch | Impartial reviews & price comparison

Overview

The Forerunner is a running watch family by Garmin.

The Forerunner 645 was released in 2019. The latest model in the family is the Garmin Forerunner 265S.

Based on our monitoring of prices across the internet, it's currently in the cheapest 30% of running watches today.

Garmin Forerunner 645 alternatives

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	‌ ‌ Now viewing ‌ Garmin Forerunner 645	‌ ‌ ‌ Garmin Fenix 8 AMOLED Sapphire 43mm	‌ ‌ ‌ Garmin MARQ Athlete	‌ ‌ ‌ Garmin MARQ Captain	‌ ‌ ‌ Garmin MARQ Aviator	‌ ‌ ‌ Garmin Fenix 8 AMOLED 47mm
bestDeal	Show prices
priceBand	Price band
released	Released Jul 2019		Oct 2022	Oct 2022	Oct 2022
Battery life	Battery life 168 hours	240 hours	288 hours	288 hours	288 hours	384 hours
Battery life – GPS mode	Battery life – GPS mode 14 hours	28 hours	28 hours	28 hours	28 hours	47 hours
Screen size	Screen size 30 mm	33 mm	30 mm	30 mm	30 mm	36 mm
Weight	Weight 42 g	60 g	94 g	88 g	144 g	80 g
Height	Height 43 mm	43 mm	46 mm	46 mm	46 mm	47 mm
Resolution	Resolution 240 x 240 px	416 x 416 px	240 x 240 px	240 x 240 px	240 x 240 px	454 x 454 px
Waterproof depth	Waterproof depth 50 m		100 m	100 m	100 m
Pixel density	Pixel density 283 ppi	452 ppi	283 ppi	283 ppi	283 ppi	458 ppi
Charging time	Charging time 2 hours
Internal storage	Internal storage	32 GB	32 GB	32 GB		32 GB
Health tracking features	Health tracking features BMI tracking Calorie burn tracking Period notifications Sleep tracking Temperature tracking	BMI tracking Calorie burn tracking Calorie intake tracking Fertility notifications Ovulation prediction Period notifications Period start date predictions Sleep tracking Temperature tracking Water intake tracking Weight tracking	BMI tracking Calorie burn tracking Fertility notifications Ovulation prediction Period notifications Period start date predictions Sleep tracking Temperature tracking Water intake tracking	BMI tracking Calorie burn tracking Fertility notifications Ovulation prediction Period notifications Period start date predictions Sleep tracking Temperature tracking Water intake tracking	BMI tracking Calorie burn tracking Fertility notifications Ovulation prediction Period notifications Period start date predictions Sleep tracking Temperature tracking Water intake tracking	BMI tracking Calorie burn tracking Calorie intake tracking Fertility notifications Ovulation prediction Period notifications Period start date predictions Sleep tracking Temperature tracking Water intake tracking Weight tracking
Sensors	Sensors Accelerometer Barometer Body temperature sensor Cadence sensor Compass Galileo GPS Gyroscope Heart rate monitor	Accelerometer Barometer Blood oxygenation monitor Body temperature sensor Compass Fast GPS lock Galileo GPS Gyroscope Has a wind speed sensor Heart rate monitor	Accelerometer Barometer Blood oxygenation monitor Cadence sensor Compass Galileo GPS Gyroscope Heart rate monitor	Accelerometer Barometer Blood oxygenation monitor Cadence sensor Compass Galileo GPS Gyroscope Heart rate monitor	Accelerometer Barometer Blood oxygenation monitor Cadence sensor Compass Galileo GPS Gyroscope Heart rate monitor	Accelerometer Barometer Blood oxygenation monitor Body temperature sensor Compass Fast GPS lock Galileo GPS Gyroscope Has a wind speed sensor Heart rate monitor
Alerts	Alerts Inactivity alerts Vibrating alerts	Inactivity alerts Irregular heart rate warnings Silent alarm Thunderstorm warnings Vibrating alerts Voice feedback	Inactivity alerts Irregular heart rate warnings Silent alarm Vibrating alerts Voice feedback	Inactivity alerts Silent alarm Vibrating alerts Voice feedback	Inactivity alerts Silent alarm Vibrating alerts Voice feedback	Inactivity alerts Irregular heart rate warnings Silent alarm Thunderstorm warnings Vibrating alerts Voice feedback
Screen features	Screen features Force touch	Always-on display Sapphire glass Touch screen	Always-on display Sapphire glass	Always-on display Sapphire glass	Always-on display Sapphire glass	Always-on display Touch screen
Common characteristics Activity detectionActivity taggingCoachingDistance trackingElevation trackingGoal settingLive trackingPace measurementRoute uploadsSteps trackingSwim stroke counterSwim stroke recognitionTrackback modeANT+Automatic syncingCloud syncingMac OS X compatibleNFCWi-FiWireless syncingIP67Sweat resistantCompatible heart monitorCompatible smart scalesBattery level indicatorRechargeable battery

Garmin Forerunner 645: 1 Expert video review

Garmin Forerunner 645 characteristics and specifications

Characteristics
Sports	Running (+112)
Brand	Garmin (+72)
Features	Achievements (+77)Auto pause (+74)Calendar sync (+56)Call control (+62)Fall detection (+40)has fast/slow heart rate notifications (+69)measures resting heart rate (+72)measures VO2 max (+68)Multi-sport mode (+75)Music playback (+71)Phone locator (+69)Sunrise/sunset time (+69)Uploadable maps (+52)Widgets (+74)
Activity Tracking Features	Activity detection (+84)Activity tagging (+93)Coaching (+60)Distance tracking (+98)Elevation tracking (+90)Goal setting (+67)Live tracking (+51)Pace measurement (+97)Route uploads (+67)Steps tracking (+97)Swim stroke counter (+84)Swim stroke recognition (+47)Trackback mode (+65)
Health tracking features	BMI tracking (+50)Calorie burn tracking (+83)Period notifications (+54)Sleep tracking (+80)Temperature tracking (+55)
Connectivity Types	ANT+ (+68)Automatic syncing (+52)Cloud syncing (+54)Mac OS X compatible (+24)NFC (+48)Wi-Fi (+52)Wireless syncing (+64)
Sensors	Accelerometer (+95)Barometer (+80)Body temperature sensor (+61)Cadence sensor (+46)Compass (+87)Galileo (+52)GPS (+97)Gyroscope (+70)Heart rate monitor (+90)
Waterproofings	IP67 (+85)Sweat resistant (+88)
Alerts	Inactivity alerts (+67)Vibrating alerts (+79)
Supported peripherals	Compatible heart monitor (+77)Compatible smart scales (+54)
Screen features	Force touch (+3)
Battery features	Battery level indicator (+63)Rechargeable battery (+98)
Colorways	Black, Sandstone

Specifications		vs Average
Model	645
Released	Jul 2019
Battery
Charging time	2 hours
Battery life – GPS mode	14 hours
Battery life	168 hours
System
Bluetooth version	4 mm
Measurements
Volume	24 cm³
Strap width	20 mm
Width	43 mm
Height	43 mm
Thickness	14 mm
Weight	42 g
Waterproofing
Waterproof depth	50 m
Screen
Pixel density	283 ppi
Resolution	240 x 240 px
Screen size	30 mm