Garmin Forerunner 645 Music vs Garmin Forerunner 70

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Forerunner 645 Music compared with Forerunner 70

	GarminForerunner 645 Music	GarminForerunner 70
Overview
Released
Released	2018	May 2026
Display
Case sizes
Case sizes	42.5 mm	42.6 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.	1.2-inch (30.4 mm diameter) colour AMOLED touchscreen, 390 x 390 pixels; optional always-on display and large-font setting; five physical buttons
Screen protection
Screen protection	Chemically strengthened glass.	Chemically strengthened glass
Health and fitness
ECG
ECG	No	No
Blood oxygen
Blood oxygen	No	Yes
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	Single-band	Single-band
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; Pulse Ox; accelerometer; ambient light sensor; no built-in barometric altimeter or body-temperature sensor
Health features
Health features	All-day heart rate, steps, sleep and intensity minutes.	Continuous heart rate with high/low alerts; HRV status; Body Battery; stress and respiration; advanced sleep, sleep coach, breathing variations and nap detection; smart wake alarm; Health Snapshot; lifestyle logging; Health Status; women's health tracking via Garmin Connect; no ECG app
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.	More than 80 sports apps; training readiness, status, load, load focus and recovery time; Garmin running, cycling and strength coaching; daily suggested running workouts including run/walk; quick workouts; wrist-based running dynamics and running power; PacePro; VO2 max and race predictions; breadcrumb course navigation, back-to-start and TracBack; pool swimming; no open-water swim or triathlon mode; no full offline maps
Safety features
Safety features	–	Incident detection during selected activities, assistance and LiveTrack require a paired compatible smartphone; live event sharing is Android-only; screen flashlight, not a separate LED torch
Battery and connections
Battery life (maker's claim)
Battery life (maker's claim)	Up to 7 days	Up to 13 days
In low-power mode
In low-power mode	–	Up to 28 days
Mobile data option
Mobile data option	No	No
Works with
Works with	iPhone and Android	iPhone and Android
Battery life detail
Battery life detail	Up to seven days in smartwatch mode or five hours with GPS and music according to the exact model's Garmin Singapore specification table. Its prose also says 14 GPS hours without stating a music-use condition.	Smartwatch up to 13 days, or 5 days with display always on; battery saver smartwatch up to 28 days; GPS-only GNSS up to 23 hours; all-systems GNSS up to 16 hours; actual life depends on enabled features and usage
Charging
Charging	Rechargeable battery with Garmin charging cable.	Garmin proprietary plug charging/data cable; rechargeable built-in lithium-ion battery; USB charging temperature 0–45 °C
Connectivity
Connectivity	Bluetooth, ANT+ and Wi-Fi; Garmin Pay, smart notifications, Connect IQ, LiveTrack and on-watch music playback to Bluetooth headphones.	Bluetooth and ANT+; GPS, GLONASS and Galileo; no multi-band GNSS; Android-only text responses and notification images; Connect IQ apps/watch faces/data fields; Garmin Share; controls smartphone music without offline playback; no Garmin Pay, speaker/microphone calls or cellular connection
Storage
Storage	Up to 500 songs and 200 hours of activity history.	512 MB memory/history; not storage for offline music playback
Design
Weight (lightest version)
Weight (lightest version)	42.2 g	40 g (better)
Software
Software	Garmin	Garmin
Case materials
Case materials	Stainless steel bezel, chemically strengthened glass and silicone band; 5 ATM water rating.	Fibre-reinforced polymer bezel; silicone band; chemically strengthened glass; 5 ATM water rating; operating/storage temperature –20–60 °C
Size
Size	42.5 x 42.5 x 13.5 mm; 42.2 g.	42.6 x 42.6 x 11.9 mm; Garmin lists 40 g without a separate body-only weight
Bands
Bands	Quick-release 20 mm band; fits wrists 127–204 mm.	Standard 20 mm quick-release silicone band; fits 126–203 mm wrists
Colours
Colours	Black band and case with rose-gold hardware.	UK Black, Whitestone, Citron and Cool Lavender; global range additionally offers Tidal Blue and Soft Pink
In the box
In the box	–	Forerunner 70; charging cable; documentation