Garmin Forerunner 645 Specs (Detailed) – Comparison to FR 630 and FR 235

It’s pretty obvious that the new Forerunner 645 Music has, errr, music. But is there anything else to tickle your running fancy? Let’s do some detailed comparisons and compare to other Forerunners.


Garmin Forerunner 645 Review Music
235 – 645 Music – 935

I think it’s interesting to compare the ‘proper’ run-focussed Forerunners ie the 235 and 630.

The 735XT and 935 just have all the multisport stuff to get in the way and befuddle our brains. Plus many of you simply won’t swim and run (you strange lot !! 😉 ) Just in case you are interested in the multisport comaprisons check the follwoing link out first…

ESSENTIAL READING: Forerunner 645 vs 935 vs 735XT Comparison & Specs


Back to the proper running watches…235 and 630.

The detailed comparison is further below (Source: but here is my takeaway summary and headlines if you are pushed for time.

Garmin 645 Bible ⌚ Garmin 645 Review Forerunner Music


  • It looks to have everything a running watch could ever ‘need’.
  • Personally I would prefer a sports watch appearance, but Garmin have probably made the right call with this design for the broader target market of runners
  • It’s expensive BUT the onboard MUSIC could make this a ‘Kerching moment’ for Garmin’s accountants.
  • The Forerunner 645 is clearly different from other Garmins in the Forerunner range.


The Forerunner 645 has notably more functionality than the 630 and 235 although on pure ‘competitive’ running features the 630 and 645 are similar. You might have to think about justifying your upgrade from your 630 but the upgrade from the 235 is a much easier call with many obvious differences. If you don’t do multisports then there is no real reason to go for the 935/Fenix 5 alternatives (discussed yesterday; link to: For customers, the big pull of new stuff in the 645 will come from ONBOARD MUSIC and GARMIN PAY, both will be highly desirable features for MANY casual to serious runners.

  • New format compared to style of the Forerunner 630 / 235
  • Strong glass yet overall ‘lightweight’ form
  • Standard bands
  • Improved screen resolution at 240x240px, but this still lacks behind smart watches and most Suunto Spartan models.
  • It looks like the touchscreen from the 630 is no more – but that is NOT confirmed.
  • Battery life looks low. But without MUSIC playing I *HOPE* it will be well over 10 hours.
  • Lots of connectivity – probably every key function
  • Music with c800 onboard songs and BLE headphone connectivity
  • Garmin Pay (contactless effectively won’t be widely avaialble until 2018)
  • It’s a cycling watch BUT it will NOT support your power meter
  • It’s a pool swim watch BUT will not cache underwater HR from HRM-TRI. Not really designed for open water use with restricted functionality there.
  • It’s not a triathlon watch ie it does not have multi-sport profiles
  • It has all the activity tracking functionality.
  • Supports both BLE and ANT+ sensors
  • Has all the clever Firstbeat physiological functionality
  • Will support CIQ 2.4 – so you will get access to any new apps as they are made available
  • ‘Obviously’ it will support Garmin’s Running Power
Best REI/Wiggle/PMC price is linked to. Prices approx $400-$450 or £480-£520 and UNlikely for non-Music to fall below $400 in 2019.

Advice to Garmin Stockists

Go long young padawan

There are LOTS more runners than triathletes. Don’t be too worried about runners’ relative reluctance to spend money on gadgets as the 645 is opening up previously untapped market segments with GARMIN PAY and MUSIC. You won’t be able to get all the stock you want anyway 🙁 And when you can the price undercutting will start, albeit surupticiously at first.

I adapted the table from and have corrected some errors I spotted there, please let me know if there are any more.

Garmin Forerunner 645 MusicGarmin Forerunner 630Garmin Forerunner 235
Top-end running WatchTop-end running WatchMid-level Running Watch
Headline RRP USA$450$400$300
Lens MaterialCorning® Gorilla® Glass 3chemically strengthened glasschemically strengthened glass
Bezel Materialstainless steel
Case material
QuickFit™ watch band compatible
Quick Release Bandsyes (20 mm, Industry standard)
Strap materialsiliconesiliconesilicone
Physical size42.5 x 42.5 x 13.5 mm45 x 45 x 11.7 mm45 x 45 x 11.7 mm
Weight42.2 g44 g42 g
Water rating5 ATM5 ATM5 ATM
Display typesunlight-visible, transflective memory-in-pixel (MIP)sunlight-visible, transflective memory-in-pixel (MIP)sunlight-visible, transflective memory-in-pixel (MIP)
Display size1.2″ (30.4 mm) diameter1.23″ (31.1 mm) diameter1.23″ (31.1 mm) diameter
Display resolution240 x 240 pixels215 x 180 pixels215 x 180 pixels
Color displayYesYes
Battery lifeSmartwatch Mode: Up to 7 daysSmartwatch Mode: Up to 4 weeksSmartwatch Mode: Up to 9 days
GPS mode with music: Up to 5 hoursGPS mode: Up to 16 hoursGPS mode: Up to 11 hours
Memory/History200 hours of activity data200 hours of activity data200 hours of activity data
Clock Features
GPS Time SyncYesYesYes
Automatic daylight saving timeYesYesYes
Alarm clockYesYesYes
Sunrise/sunset timesYesNoNo
Face It™ watch face creatorYesYesYes
Garmin Elevate™ wrist heart rate monitorYesNoYes
Barometric altimeterYesNoNo
Daily Smart Features
ConnectivityBluetooth®, ANT+®, Wi-Fi®YesYes
Connect IQ™ (downloadable watch faces, data fields, widgets and apps)YesYesYes
Smart notificationsYesYesYes
Text response/reject phone call with text (Android™ only)YesNoNo
Music controlsYesYesYes
Plays Onboard MusicYesNoNo
Music Storageup to 800 songsNoNo
Find My PhoneYesYesYes
Find My WatchYesNoNo
VIRB® remoteYesYesYes
Smartphone compatibilityiPhone® and Android™YesYes
Compatible with Garmin Connect™ MobileYesYesYes
Garmin Pay™Yes
Activity Tracking Features
Step counterYesYesYes
Move bar (displays on device after a period of inactivity; walk for a couple of minutes to reset it)YesYesYes
Auto goal (learns your activity level and assigns a daily step goal)YesYesYes
Sleep monitoring (monitors total sleep and periods of movement or restful sleep)YesYesYes
Calories burnedYesYesYes
Floors climbedYesNoNo
Distance traveledYesYesYes
Intensity minutesYesYesYes
Move IQ™YesYesYes
Fitness Ageyes (in app)YesYes
Fitness Equipment/Gym
Preloaded gym activity profilesStrength Training, Cardio Training, Elliptical Training, Stair Stepping, Floor Climbing, Indoor Rowing and YogaNoNo
Cardio workoutsYesNoNo
Strength workoutsYesNoNo
Automatic rep countingYesNoNo
Training, Planning and Analysis Features
GPS speed and distanceYesYesYes
Customizable data pagesYesYesYes
Customizable activity profilesYesYesYes
Auto Pause®YesYesYes
Advanced workoutsYesYesYes
Downloadable training plansYesYesYes
Auto Lap®YesYesYes
Manual lapYesYesYes
Virtual PartnerYesYesNo
Configurable lap alertsYesYesNo
V02 maxYesYesYes
Training Status (lets you see if you’re training effectively by tracking your training history and fitness level trend.)YesNoNo
Training Load (your total training load for the last 7 days calculated from estimated EPOC)YesNoNo
Training Effect (aerobic)YesYesYes
Training Effect (anaerobic)YesNoNo
Customizable alertsYesYesYes
Audio promptsYesYesYes
Finish timeYesYesYes
Race an ActivityYesYesNo
Auto multisport activitiesYesNoNo
Manual multisport activitiesYesNo?No?
Course guidanceYesYesNo
Segments (Live, Garmin)YesNoNo
Strava features (Beacon, live segments)YesNoNo
Group LiveTrackYesNoNo
Touch and/or button lockYesYesYes
Hot keysNoNoNo
Auto scrollYesYesYes
Activity history on watchYesYesYes
Heart Rate Features
HR zonesYesyes (with HRM)Yes
HR alertsYesyes (with HRM)Yes
HR caloriesYesyes (with HRM)Yes
% HR maxYesyes (with HRM)No
% HRRYesyes (with HRM)No
Recovery timeYesyes (with HRM)Yes
Auto max HRYesyes (with HRM)No
HRV stress test (measures your heart rate variability while standing still, for 3 minutes, to provide you with an estimated stress level; the scale of this is 1 to 100; low scores indicate lower stress levels)yes (with compatible accessory?)yes (with HRM)No
Records heart rate while swimmingyes (with compatible accessory)NoNo
HR Broadcast (broadcasts HR data over ANT+™ to paired devices)YesNoYes
Running Features
Preloaded run profilesRunning, Treadmill Running, Indoor TrackYesYes
GPS-based distance, time and paceYesYesYes
Running dynamics (with accessory)YesYesNo
Vertical oscillation and ratio (with accessory)YesYesNo
Ground contact time and balance (with accessory)YesYesNo
Stride length with accessory)YesYesNo
Performance conditionYesyes (with HRM?)No
Lactate threshold (with accessory)YesYesNo
Run workoutsYesYesYes
Race predictorYesYesYes
Foot pod capableYesYesYes
Outdoor Recreation Features
Preloaded outdoor recreation profilesSkiing, Snowboarding, XC Skiing, Stand up Paddleboarding, RowingYesYes
Point-to-point navigationYesNoNo
Bread crumb trail in real timeYesNoNo
Back to startYesYesYes
UltraTrac modeYesNoNo
Elevation profileYesNoNo
Distance to destinationYesYes (back to start)Yes (back to start)
Barometric trend indicatorNoNoNo
Storm alertNoNoNo
Trail run auto climbNoNoNo
Vertical speedYesNoNo
Total ascent/descentYesNoNo
Compatible with BaseCamp™YesNoNo
GPS coordinatesYesNoNo
Projected waypointNoNoNo
Sight ‘N GoNoNoNo
Area calculationNoNoNo
Hunt/fish calendarNoNoNo
Sun and moon informationNoNoNo
Dual grid coordinatesNoNoNo
Cycling Features
Preloaded cycling profilesBiking, Indoor BikingYesYes
Bike lap and lap maximum power (with power sensor)No PowerNoNo
Race an activityYesYesNo
Time/distance alerts (triggers alarm when you reach goal)YesYesYes
Interval trainingYesYesYes
FTP (with accessory)NoNoNo
Compatible with Vector™ (power meter)No PowerNoNo
Power meter compatible (displays power data from compatible third-party ANT+™-enabled power meters)No PowerNoNo
Compatible with Varia Vision™ (head-mounted display)YesYesYes
Compatible with Varia™ radar (rear-facing radar)YesYesYes
Compatible with Varia™ lightsYesYesYes
Speed and cadence sensor support (with sensor)yes (ANT+® and Bluetooth® Smart)YesYes
Swimming Features
Preloaded swim profilesPool SwimmingNoNo
Pool swim metrics (lengths, distance, pace, stroke count/rate, calories)YesNoNo
Stroke type detection (freestyle, backstroke, breaststroke, butterfly)YesNoNo
Swim efficiency (SWOLF)YesNoNo
Drill loggingYesNoNo
Pool swim workoutsYesNoNo
Open-water swim metrics (distance, pace, stroke count/rate, stroke distance, calories)NoNoNo
Heart rate (real-time during rests, interval and session stats during rests, and automatic heart rate download post-swim)NoNoNo
Best REI/Wiggle/PMC price is linked to. Prices approx $400-$450 or £480-£520 and UNlikely for non-Music to fall below $400 in 2019.

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10 thoughts on “Garmin Forerunner 645 Specs (Detailed) – Comparison to FR 630 and FR 235

  1. Does this mean that even if you have the HRM-TRI, you will not be able to get heart rate data when you swim laps? Seems like it wouldn’t require anything additional in terms of sensors, hardware or connectivity…

    1. no swim hr data in swim..that’s what it says on (there are ciq apps….not too great tho, i tried one on 235 on hols..kinda worked … but….
      yep i guess the hardwre is all there.

      it’s product differentition. if my marketing knowledge serves me correctly.

      1. Yes I have the power race app. I was talking about an app that lets you do structured, power zones based work out.
        It could make sense to skip this version and get the next one if this function is implemented. To be honest I wouldn’t be terribly shocked if garmin released yet a new watch in the first 6 months of 2018. They might do so in order to meet the wishes of people like me in view of the fact that they now offer they own power meters.
        What do you think?

      2. yes
        totally fair point about the workouts. no it can’t be yes. yes it needs to be done. its complex tho. work needs to be done on the ant+ spec for power. AFAIK that IS being looked at by the 3x manufs. so it WILL come.
        new watch: yep, my understandings/assumptions are that there will be a new fenix evolution in q1.2017 but that is to address hardware issues probably under the guise of additional functionality. anyway that still will NOT have the power zones you describe as that must come from the ant working group (AWG…look for that acronym)

      1. I like it because that’s the one I have 🙂 but also BT, ANT and storage is cool

        No never tried the Garmins

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