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

FTC: Affiliate Disclosure: All links pay commission

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 Music Garmin Forerunner 630 Garmin Forerunner 235
Top-end running Watch Top-end running Watch Mid-level Running Watch
Headline RRP USA $450 $400 $300
Lens Material Corning® Gorilla® Glass 3 chemically strengthened glass chemically strengthened glass
Bezel Material stainless steel
Case material
QuickFit™ watch band compatible
Quick Release Bands yes (20 mm, Industry standard)
Strap material silicone silicone silicone
Physical size 42.5 x 42.5 x 13.5 mm 45 x 45 x 11.7 mm 45 x 45 x 11.7 mm
Weight 42.2 g 44 g 42 g
Water rating 5 ATM 5 ATM 5 ATM
Display type sunlight-visible, transflective memory-in-pixel (MIP) sunlight-visible, transflective memory-in-pixel (MIP) sunlight-visible, transflective memory-in-pixel (MIP)
Display size 1.2″ (30.4 mm) diameter 1.23″ (31.1 mm) diameter 1.23″ (31.1 mm) diameter
Display resolution 240 x 240 pixels 215 x 180 pixels 215 x 180 pixels
Color display Yes Yes
Battery life Smartwatch Mode: Up to 7 days Smartwatch Mode: Up to 4 weeks Smartwatch Mode: Up to 9 days
GPS mode with music: Up to 5 hours GPS mode: Up to 16 hours GPS mode: Up to 11 hours
Memory/History 200 hours of activity data 200 hours of activity data 200 hours of activity data
Clock Features
Time/date Yes Yes Yes
GPS Time Sync Yes Yes Yes
Automatic daylight saving time Yes Yes Yes
Alarm clock Yes Yes Yes
Timer Yes Yes Yes
Stopwatch Yes Yes Yes
Sunrise/sunset times Yes No No
Face It™ watch face creator Yes Yes Yes
GPS Yes Yes Yes
Garmin Elevate™ wrist heart rate monitor Yes No Yes
Barometric altimeter Yes No No
Compass Yes Yes No
Gyroscope Yes No No
Accelerometer Yes Yes Yes
Thermometer Yes No No
Daily Smart Features
Connectivity Bluetooth®, ANT+®, Wi-Fi® Yes Yes
Connect IQ™ (downloadable watch faces, data fields, widgets and apps) Yes Yes Yes
Smart notifications Yes Yes Yes
Text response/reject phone call with text (Android™ only) Yes No No
Calendar Yes Yes Yes
Weather Yes Yes Yes
Music controls Yes Yes Yes
Plays Onboard Music Yes No No
Music Storage up to 800 songs No No
Find My Phone Yes Yes Yes
Find My Watch Yes No No
VIRB® remote Yes Yes Yes
Smartphone compatibility iPhone® and Android™ Yes Yes
Compatible with Garmin Connect™ Mobile Yes Yes Yes
Garmin Pay™ Yes
Activity Tracking Features
Step counter Yes Yes Yes
Move bar (displays on device after a period of inactivity; walk for a couple of minutes to reset it) Yes Yes Yes
Auto goal (learns your activity level and assigns a daily step goal) Yes Yes Yes
Sleep monitoring (monitors total sleep and periods of movement or restful sleep) Yes Yes Yes
Calories burned Yes Yes Yes
Floors climbed Yes No No
Distance traveled Yes Yes Yes
Intensity minutes Yes Yes Yes
TrueUp™ Yes Yes Yes
Move IQ™ Yes Yes Yes
Fitness Age yes (in app) Yes Yes
Fitness Equipment/Gym
Preloaded gym activity profiles Strength Training, Cardio Training, Elliptical Training, Stair Stepping, Floor Climbing, Indoor Rowing and Yoga No No
Cardio workouts Yes No No
Strength workouts Yes No No
Automatic rep counting Yes No No
Training, Planning and Analysis Features
GPS speed and distance Yes Yes Yes
Customizable data pages Yes Yes Yes
Customizable activity profiles Yes Yes Yes
Auto Pause® Yes Yes Yes
Advanced workouts Yes Yes Yes
Downloadable training plans Yes Yes Yes
Auto Lap® Yes Yes Yes
Manual lap Yes Yes Yes
Virtual Partner Yes Yes No
Configurable lap alerts Yes Yes No
V02 max Yes Yes Yes
Training Status (lets you see if you’re training effectively by tracking your training history and fitness level trend.) Yes No No
Training Load (your total training load for the last 7 days calculated from estimated EPOC) Yes No No
Training Effect (aerobic) Yes Yes Yes
Training Effect (anaerobic) Yes No No
Customizable alerts Yes Yes Yes
Audio prompts Yes Yes Yes
Finish time Yes Yes Yes
Race an Activity Yes Yes No
Auto multisport activities Yes No No
Manual multisport activities Yes No? No?
Course guidance Yes Yes No
Segments (Live, Garmin) Yes No No
Strava features (Beacon, live segments) Yes No No
LiveTrack Yes No No
Group LiveTrack Yes No No
Touch and/or button lock Yes Yes Yes
Hot keys No No No
Auto scroll Yes Yes Yes
Activity history on watch Yes Yes Yes
Heart Rate Features
HR zones Yes yes (with HRM) Yes
HR alerts Yes yes (with HRM) Yes
HR calories Yes yes (with HRM) Yes
% HR max Yes yes (with HRM) No
% HRR Yes yes (with HRM) No
Recovery time Yes yes (with HRM) Yes
Auto max HR Yes yes (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 swimming yes (with compatible accessory) No No
HR Broadcast (broadcasts HR data over ANT+™ to paired devices) Yes No Yes
Running Features
Preloaded run profiles Running, Treadmill Running, Indoor Track Yes Yes
GPS-based distance, time and pace Yes Yes Yes
Running dynamics (with accessory) Yes Yes No
Vertical oscillation and ratio (with accessory) Yes Yes No
Ground contact time and balance (with accessory) Yes Yes No
Stride length with accessory) Yes Yes No
Cadence Yes Yes Yes
Performance condition Yes yes (with HRM?) No
Lactate threshold (with accessory) Yes Yes No
Run workouts Yes Yes Yes
Race predictor Yes Yes Yes
Foot pod capable Yes Yes Yes
Outdoor Recreation Features
Preloaded outdoor recreation profiles Skiing, Snowboarding, XC Skiing, Stand up Paddleboarding, Rowing Yes Yes
Point-to-point navigation Yes No No
Bread crumb trail in real time Yes No No
Back to start Yes Yes Yes
TracBack® Yes No No
UltraTrac mode Yes No No
Elevation profile Yes No No
Distance to destination Yes Yes (back to start) Yes (back to start)
Barometric trend indicator No No No
Storm alert No No No
Trail run auto climb No No No
Vertical speed Yes No No
Total ascent/descent Yes No No
Compatible with BaseCamp™ Yes No No
GPS coordinates Yes No No
Projected waypoint No No No
Sight ‘N Go No No No
Area calculation No No No
Hunt/fish calendar No No No
Sun and moon information No No No
Dual grid coordinates No No No
Cycling Features
Preloaded cycling profiles Biking, Indoor Biking Yes Yes
Courses Yes Yes No
Bike lap and lap maximum power (with power sensor) No Power No No
Race an activity Yes Yes No
Time/distance alerts (triggers alarm when you reach goal) Yes Yes Yes
Interval training Yes Yes Yes
FTP (with accessory) No No No
Compatible with Vector™ (power meter) No Power No No
No No
Power meter compatible (displays power data from compatible third-party ANT+™-enabled power meters) No Power No No
Compatible with Varia Vision™ (head-mounted display) Yes Yes Yes
Compatible with Varia™ radar (rear-facing radar) Yes Yes Yes
Compatible with Varia™ lights Yes Yes Yes
Speed and cadence sensor support (with sensor) yes (ANT+® and Bluetooth® Smart) Yes Yes
Swimming Features
Preloaded swim profiles Pool Swimming No No
Pool swim metrics (lengths, distance, pace, stroke count/rate, calories) Yes No No
Stroke type detection (freestyle, backstroke, breaststroke, butterfly) Yes No No
Swim efficiency (SWOLF) Yes No No
Drill logging Yes No No
Pool swim workouts Yes No No
Open-water swim metrics (distance, pace, stroke count/rate, stroke distance, calories) No No No
Heart rate (real-time during rests, interval and session stats during rests, and automatic heart rate download post-swim) No No No
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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Ben Fuld

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…


I guess this Watch will not support alarms for power zones training will it?


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?


Now just need Wahoo to update their TickrX to output running dynamics & I’m set!


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

No never tried the Garmins

John Kissane