Garmin Forerunner 265 vs Garmin Forerunner 645

Every spec side by side, from each maker's published figures.

Only show differences

Better figure, where one is clearly better

Share comparison

Forerunner 265 compared with Forerunner 645

	GarminForerunner 265	GarminForerunner 645
Overview
Released
Released	March 2023	2018
Display
Case sizes
Case sizes	42 mm or 46 mm	42.5 mm
Panel
Panel	OLED	Memory-in-pixel
Always-on display
Always-on display	Yes	Yes
Display detail
Display detail	Forerunner 265S has a 1.1″ (28.1 mm) AMOLED touchscreen, 360 x 360 pixels; Forerunner 265 has a 1.3″ (32.5 mm) AMOLED touchscreen, 416 x 416 pixels; five buttons; optional always-on mode	1.2-inch (30.4 mm) sunlight-readable transflective colour MIP display, 240 x 240 pixels, with five-button control.
Screen protection
Screen protection	Corning Gorilla Glass 3	Chemically strengthened glass.
Health and fitness
ECG
ECG	No	No
Blood oxygen
Blood oxygen	Yes	No
Skin temperature
Skin temperature	No	No
Sleep apnoea alerts
Sleep apnoea alerts	No	No
High blood pressure alerts
High blood pressure alerts	No	No
Body composition
Body composition	No	No
Fall detection
Fall detection	No	No
Crash detection
Crash detection	No	No
GPS
GPS	Dual-band (L1 and L5)	Single-band
Water resistance
Water resistance	50 m	50 m
Sensors
Sensors	Garmin Elevate wrist heart rate monitor; Pulse Ox blood oxygen monitor; barometric altimeter; compass; gyroscope; accelerometer; thermometer; ambient light sensor	GPS, GLONASS, Garmin Elevate wrist heart rate, barometric altimeter, compass, gyroscope, accelerometer and thermometer.
Health features
Health features	High and low heart rate alerts; HRV status; Body Battery; all-day stress; sleep score, sleep coach and nap detection; breathing variations; respiration rate; Health Snapshot; menstrual cycle and pregnancy tracking; jet lag adviser	All-day heart rate, steps, sleep and intensity minutes.
Fitness features
Fitness features	Training readiness and training status; training load, load ratio and load focus; training effect, VO2 max and recovery time; wrist-based running power and dynamics; PacePro; race predictor; Garmin Coach running, cycling and strength plans; daily suggested running and cycling workouts; triathlon and open-water swimming; course navigation with a breadcrumb trail, TracBack and Up Ahead	Running, indoor running, cycling, pool swimming, skiing and rowing profiles; training status and load, aerobic and anaerobic training effect, VO2 max, recovery time and breadcrumb course guidance. Detailed running dynamics require an HRM strap or Running Dynamics Pod.
Safety features
Safety features	Incident detection during select activities; assistance; LiveTrack; spectator messaging; live event sharing (Android only); these features require a paired phone	–
Battery and connections
Battery life (maker's claim)
Battery life (maker's claim)	Up to 15 days	Up to 7 days
Mobile data option
Mobile data option	No	No
Works with
Works with	iPhone and Android	iPhone and Android
Storage
Storage	8 GB	–
Battery life detail
Battery life detail	Forerunner 265S up to 15 days in smartwatch mode, 24 hours GPS only, 18 hours SatIQ (AutoSelect), 15 hours All-Systems + Multi-Band; with music up to 7.5, seven and six hours respectively. Forerunner 265 up to 13 days in smartwatch mode, 20 hours GPS only, 16 hours SatIQ, 14 hours All-Systems + Multi-Band; with music up to seven, 6.5 and six hours respectively	Up to seven days in smartwatch mode or 14 hours in GPS mode per the exact model's Garmin specification table. The same page's prose says 12 GPS hours; its table and headline say 14.
Charging
Charging	Garmin proprietary plug charger; USB-C charging/data cable included	Rechargeable battery with Garmin charging cable.
Connectivity
Connectivity	Bluetooth, ANT+ and Wi-Fi; multi-band GPS with GPS, GLONASS, Galileo, QZSS, BeiDou and SatIQ; Garmin Pay; offline music from Spotify, Deezer and Amazon Music (premium subscription required); Connect IQ; notifications and Android text responses; Garmin Share	Bluetooth, ANT+ and Wi-Fi; Garmin Pay, smart notifications, Connect IQ, LiveTrack and phone music controls. No on-watch music storage.
Storage
Storage	–	Stores 200 hours of activity history.
Design
Weight (lightest version)
Weight (lightest version)	39 g (better)	42.2 g
Software
Software	Garmin	Garmin
Case materials
Case materials	Fibre-reinforced polymer bezel; silicone band; 5 ATM water rating	Stainless steel bezel, chemically strengthened glass and silicone band; 5 ATM water rating.
Size
Size	Forerunner 265S is 41.7 x 41.7 x 12.9 mm and 39 g; Forerunner 265 is 46.1 x 46.1 x 12.9 mm and 47 g; Garmin does not publish case-only weights	42.5 x 42.5 x 13.5 mm; 42.2 g.
Bands
Bands	Quick-release 18 mm bands for the 265S, fitting 115–178 mm wrists; quick-release 22 mm bands for the 265, fitting 135–205 mm wrists	Quick-release 20 mm band; fits wrists 127–204 mm.
Colours
Colours	–	Black band with silver-toned bezel.
In the box
In the box	Forerunner 265 or 265S, USB-C charging/data cable, documentation	–