Garmin · 2018
Forerunner® 645 MusicSize, Dimensions & Wrist Fit
Case Width
42.5mm
Thickness
13.5mm
Diameter
42.5mm
Weight
42.2g
The Garmin Forerunner® 645 Music sits best on flat wrist widths of about 45–61mm (≈ 12.0–16.3cm wrist circumference). Adjust the slider below to check your wrist.
Does the Forerunner® 645 Music fit your wrist?
Drag the slider to your wrist width and see the Forerunner® 645 Music overlaid at true scale. Lug-to-lug — not case diameter — decides whether a watch overhangs your wrist.
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Garmin Forerunner® 645 Music Full Specifications
Overview1
FamilyGarmin
General9
Battery life
Smartwatch Mode: Up to 7 daysGPS mode without music: Up to 14 hoursGPS mode with music: Up to 5 hours
Display Size1.2" (30.4 mm) diameter
Lens materialCorning® Gorilla® Glass 3
Bezel materialStainless steel
Colour displayYes
Memory/history200 hours of activity data
Strap materialSilicone
Display Resolution240 x 240 pixels
Quick release bandsYes (20 mm, Industry standard)
Sensors9
GPSYes
CompassYes
GLONASSYes
GalileoYes
GyroscopeYes
ThermometerYes
AccelerometerYes
Barometric altimeterYes
Garmin Elevate™ wrist heart rate monitorYes
Product Info5
Main SKU010-01863-30
Product ID612476
Product NameForerunner® 645 Music
Release Date1/9/2018
Product VariationWith Black Coloured Band
Clock features7
TimerYes
StopwatchYes
Time/dateYes
Alarm clockYes
GPS time syncYes
Sunrise/sunset timesYes
Automatic daylight saving timeYes
Cycling features7
CoursesYes
Race an activityYes
Compatible with Varia™ lightsYes
Speed and cadence sensor support (w/sensor)Yes
Compatible with Varia™ radar (rear-facing radar)Yes
Compatible with Varia Vision™ (head-mounted display)Yes
Alerts (triggers alarm when you reach goals including time, distance, heart rate or calories)Yes
Running features10
Run workoutsYes
Race predictorYes
Foot pod capableYes
Running dynamicsYes (with compatible accessory)
Performance conditionYes
Stride length (real time)Yes (with compatible accessory)
Vertical oscillation and ratioYes (with compatible accessory)
Ground contact time and balanceYes (with compatible accessory)
GPS-based distance, time and paceYes
Cadence (provides real-time number of steps per minute)Yes
What You'll Love2
Garmin Pay™Yes
Training StatusYes
Activity profiles4
Gym
Strength Training, Cardio Training, Elliptical Training, Stair Stepping, Floor Climbing, Indoor Rowing and Yoga
SwimPool Swimming
CyclingBiking, Indoor Biking
Outdoor recreation
Skiing, Snowboarding, XC Skiing, Stand up Paddleboarding, Rowing
Swimming features7
Countdown startYes
Pool swim workoutsYes
Drill logging (pool swim only)Yes
"Repeat on" rest timer (pool swim only)Yes
Basic rest timer (up from 0) (pool swim only)Yes
Stroke type detection (freestyle, backstroke, breaststroke, butterfly) (pool swim only)Yes
Pool swim metrics (lengths, distance, pace, stroke count, swim efficiency (SWOLF), calories)Yes
Outdoor recreation10
TracBack®Yes
Back to startYes
UltraTrac modeYes
Vertical speedYes
GPS coordinatesYes
Elevation profileYes
Total ascent/descentYes
Distance to destinationYes
Point-to-point navigationYes
Breadcrumb trail in real timeYes
Daily smart features13
CalendarYes
ConnectivityBluetooth®, ANT+®, Wi-Fi®
Find my phoneYes
Find my watchYes
Weather forecastsYes
Smart NotificationsYes
VIRB® camera remoteYes
Smartphone compatibilityiPhone® and Android™
Controls smartphone musicYes
Plays and controls watch musicYes
Compatible with Garmin Connect™ MobileYes
Text response/reject phone call with text (Android™ only)Yes
Connect IQ™ (downloadable watch faces, data fields, widgets and apps)Yes
Activity tracking features11
TrueUp™Yes
Move IQ™Yes
Step counterYes
Floors climbedYes
Calories BurnedYes
Intensity minutesYes
Distance travelledYes
Automatic rep countingYes
Garmin Connect™ Challenges appYes (optional Connect IQ app)
Auto goal (learns your activity level and assigns a daily step goal)Yes
Move alerts (displays on device after a period of inactivity; walk for a couple of minutes to reset it)Yes
Workout and Training Plans2
Cardio workoutsYes
Strength workoutsYes
Health & Wellness Monitoring8
SleepYes (Advanced)
Hydration
Yes (in Garmin Connect™ and optional Connect IQ™ widget)
Fitness AgeYes (in app)
All-day StressYes
Women's Health
Yes (in Garmin Connect™ and optional Connect IQ™ widget)
Resting heart rateYes
Relaxation Breathing TimerYes
Wrist-based heart rate (constant, every second)Yes
Safety and tracking features1
Incident Detection during select activitiesYes
Kid activity tracking features1
Toe-to-Toe™ Challenges app
Yes (optional Connect IQ Toe-to-Toe™ Challenges app)
Training, planning and analysis features34
% HRRYes
% HR MaxYes
HR ZonesYes
HR AlertsYes
Auto Lap®Yes
Manual lapYes
Auto Max HRYes
Auto scrollYes
Finish timeYes
HR CaloriesYes
Voice alertsYes
Physio TrueUpYes
Recovery TimeYes
Training LoadYes
VO2 Max (Run)Yes
Course guidanceYes
Training EffectYes
Virtual partnerYes
Race an activityYes
Advanced workoutsYes
Interval trainingYes
Customisable alertsYes
Garmin Live SegmentsYes
Strava Live SegmentsYes
Customisable screen(s)Yes
GPS speed and distanceYes
Configurable lap alertsYes
Touch and/or button lockYes
Activity history on watchYes
Downloadable training plansYes
Training Effect (Anaerobic)Yes
Customisable activity profilesYes
Auto Pause® automatic timer haltYes
HR Broadcast (broadcasts HR data over ANT+® to paired devices)Yes
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Forerunner® 645 Music — Frequently Asked Questions
What size is the Garmin Forerunner® 645 Music?
The Garmin Forerunner® 645 Music has a 42.5mm case and is 13.5mm thick.
Will the Garmin Forerunner® 645 Music fit my wrist?
The Garmin Forerunner® 645 Music looks balanced on flat wrist widths of roughly 45–61mm (about 12.0–16.3cm circumference). Use the interactive fit tool above to check against your own wrist.
How much does the Garmin Forerunner® 645 Music weigh?
The Garmin Forerunner® 645 Music weighs 42.2g (case only; straps add weight).
What is the best way to compare the Garmin Forerunner® 645 Music with other watches?
Use our side-by-side comparison tool to see the Garmin Forerunner® 645 Music next to any other watch — case size, thickness, lug-to-lug and full specs, scaled to real proportions.