Garmin Forerunner 645 vs Garmin Forerunner 970

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Forerunner 645 compared with Forerunner 970

	GarminForerunner 645	GarminForerunner 970
Overview
Released
Released	2018	May 2025
Display
Case sizes
Case sizes	42.5 mm	47 mm
Panel
Panel	Memory-in-pixel	OLED
Always-on display
Always-on display	Yes	Yes
Display detail
Display detail	1.2-inch (30.4 mm) sunlight-readable transflective colour MIP display, 240 x 240 pixels, with five-button control.	1.4″ (35.3 mm) AMOLED colour touchscreen, 454 x 454 pixels; five buttons
Screen protection
Screen protection	Chemically strengthened glass.	Sapphire crystal lens
Health and fitness
ECG
ECG	No	Yes
Blood oxygen
Blood oxygen	No	Yes
Skin temperature
Skin temperature	No	Yes
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	Single-band	Dual-band (L1 and L5)
Water resistance
Water resistance	50 m	50 m
Sensors
Sensors	GPS, GLONASS, Garmin Elevate wrist heart rate, barometric altimeter, compass, gyroscope, accelerometer and thermometer.	Garmin Elevate wrist heart rate monitor; Pulse Ox blood oxygen monitor; barometric altimeter; compass; gyroscope; accelerometer; thermometer; ambient light sensor
Health features
Health features	All-day heart rate, steps, sleep and intensity minutes.	Garmin ECG App (atrial fibrillation); Pulse Ox spot checks, with optional all-day acclimation and sleep readings; skin temperature; high and low heart rate alerts; HRV status; health status; sleep score, sleep coach, sleep alignment and nap detection; breathing variations; Body Battery; all-day stress; Health Snapshot; lifestyle logging; women's health tracking with past ovulation estimates; jet lag adviser
Fitness features
Fitness features	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.	Training readiness and training status; running tolerance; running economy and step speed loss (with HRM 600); wrist-based running dynamics and running power; VO2 max, endurance score and hill score; race predictor and projected race time; PacePro; ClimbPro; real-time stamina; Garmin Coach and Garmin Triathlon Coach plans; daily suggested workouts; quick workouts; built-in maps with turn-by-turn directions, dynamic round-trip routing and Up Ahead; triathlon and multisport profiles
Safety features
Safety features	–	Incident detection during select activities; assistance; LiveTrack; live event sharing (Android only); LED flashlight
Battery and connections
Battery life (maker's claim)
Battery life (maker's claim)	Up to 7 days	Up to 15 days
Mobile data option
Mobile data option	No	No
Works with
Works with	iPhone and Android	iPhone and Android
Storage
Storage	–	32 GB
Battery life detail
Battery life detail	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.	Smartwatch mode up to 15 days; GPS only up to 26 hours; SatIQ (AutoSelect) up to 23 hours; All-Systems + Multi-Band up to 21 hours; with music up to 14, 13 and 12 hours in the same modes
Charging
Charging	Rechargeable battery with Garmin charging cable.	Garmin charging cable with proprietary plug
Connectivity
Connectivity	Bluetooth, ANT+ and Wi-Fi; Garmin Pay, smart notifications, Connect IQ, LiveTrack and phone music controls. No on-watch music storage.	Bluetooth, ANT+ and Wi-Fi; multi-band GPS with GPS, GLONASS, Galileo, QZSS and BeiDou and SatIQ; Garmin Pay; speaker and microphone for calls and the phone's voice assistant with a paired phone; hands-free voice control
Storage
Storage	Stores 200 hours of activity history.	–
Design
Weight (lightest version)
Weight (lightest version)	42.2 g	–
Software
Software	Garmin	Garmin
Case materials
Case materials	Stainless steel bezel, chemically strengthened glass and silicone band; 5 ATM water rating.	Titanium bezel; sapphire crystal lens; 5 ATM water rating (swim); operating temperature –20 °C to 60 °C
Size
Size	42.5 x 42.5 x 13.5 mm; 42.2 g.	47 x 47 x 12.9 mm; 56 g (Garmin doesn't give a case-only weight)
Bands
Bands	Quick-release 20 mm band; fits wrists 127–204 mm.	22 mm silicone band; takes QuickFit 22 bands; fits 135–205 mm wrists
Colours
Colours	Black band with silver-toned bezel.	Carbon Grey DLC Titanium with Black case and Black/Translucent Whitestone band; Titanium with Whitestone case and Whitestone/Translucent Amp Yellow band; Soft Gold Titanium with French Grey case and French Grey/Translucent Indigo band
In the box
In the box	–	Forerunner 970, charging cable, documentation