Garmin Forerunner 645 Music Vs Vivoactive 4, Garmin Forerunner 645 Music Vs Vivoactive 3
The Forerunner 645 and vivoactive 3 are two of the best GPS running watches out right now, but choosing between the two isn’t quite a cut and dry decision. The Forerunner 645 is primarily a runner’s watch and the VA3 is truly built for the prototypical active person. As such, they each have distinct advantages and disadvantages, despite the fact that they look nearly identical (aside from extra buttons on the 645).
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In terms of features, there is a lot of overlap, so at the bottom of this post we’ve included a comparison chart. For the bulk of this comparison, we’ll focus on the relative strengths of each watch.
Garmin 645 vs vivoactive 3 – Music is huge!
There are two versions of the Forerunner 645. There’s the standard model that has an MSRP of $400
The 645 Music will be able to store up to 500 songs directly on the watch for phone-free workouts. You then just need Bluetooth earbuds and you’re good to go. If you look on Garmin’s website, they have a section that discusses compatible headphones. The 645 Music will work with most of the big name brands. Here’s Garmin’s video on music storage with the 645.
You have two options for listening to your music. Firstly, you can load your personal music onto the watch. I question how many people will do this. The other option is to join iHeartRadio All Access and download select playlists and stations to the watch. I see this as being a far more likely option, although iHeartRadio All Access starts at $10 per month.

Hold “Down” button for music menu
Having phone-free music is a big deal though, especially at the gym and during running workouts. I have dreamt of the day that I could leave my phone behind, but still get my music. To be clear, the Forerunner 645 Music has music storage, but the Forerunner 645 and vivoactive 3 do not.
Update as of Oct 2018: FR645 Music now works with Spotify!
Garmin 645 has buttons!
This is a minor point, but I like to split hairs, so let’s go. The vivoactive 3 has a touchscreen. I’m not a huge fan of touchscreens on workout watches. When my hands get sweaty, I find it hard to work with the devices. Also, I think buttons are more precise and durable. I like that the 645 uses buttons, unlike the VA3, which only has one button and then a touchscreen.
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Garmin Forerunner 645 – Advanced Running Dynamics
Again, we’re into the weeds here, but this is a relatively important point, especially for avid runners. The 645 is compatible with the HRM-Run and Running Dynamics Pod so that you can get your advanced running dynamics stats. Those include ground contact time, vertical oscillation, stride length, etc.. Here’s a video I produced that discusses these stats and the physiological measurements provided by First Beat Technologies.
Most runners probably won’t miss these metrics, but anyone that’s serious about training will like having the option to use or not use them. For example, most people can benefit from knowing more about their cadence (provided in real-time on both watches), but don’t need or care about their ground contact time balance. If you’re training for a marathon, however, you might find GCT balance to be an insightful and helpful metric. For the record, GCT balance is simply the amount of time you spend on each foot. You want it to be 50/50.
Garmin 645 vs vivoactive 3 Review Chart
MSRP | $400 or $450 for Music Version | Starts at $270 |
Check Price | Amazon | Amazon |
Size | 42.5 x 42.5 x 13.5 mm | 43.4 x 43.4 x 11.7 mm |
Weight | 42.2 g | 43.0 g |
Touchscreen | No – Buttons Only | Yes + Buttons |
Water Resistant Down to | 50 Meters | 50 Meters |
Battery Life | Up to 7 days in smartwatch mode or up to 5 hours in GPS mode with music on | Up to 7 days in smartwatch mode or up to 13 hours in GPS mode with HR on |
Interchangeable Bands | Yes – 20mm | Yes – 20mm |
GPS & GLONASS | Yes | Yes |
Wrist HRM | Yes | Yes |
Pairs with external HRMs | Yes | Yes |
Pairs with Bluetooth & ANT+ sensors | Yes | Yes |
Built-In Music Storage | Yes | No |
Music Storage | Personal, iHeartRadio All Access, Deezer coming soon… | n/a |
Garmin Pay | Yes | Yes |
Connect IQ | Yes | Yes |
All-Day Activity & Sleep Tracking | Yes | Yes |
Smartphone Notifications | Yes | Yes |
Advanced Running Dynamics | Yes w/ HRM-Run or Running Dynamics Pod | No |
Golf Support | No | Yes |
LiveTracking | Yes | Yes |
VO2 Max | Yes | Yes |
Support for Pool Swimming | Yes | Yes |
Support for Open Water Swimming | No | No |
SEE ALSO: Garmin Forerunner 645 vs Fitbit Ionic vs Apple Watch 3


VA3 also has ‘Side Swipe’, but it’s not really that helpful.
Vivoactive 3 Supports Golf
I was surprised and not surprised when I found that the Garmin FR 645 did not support golf natively. It’s a quintessential Garmin move to not include golf on a high end watch even though it’s available on much cheaper Garmin devices. In any case, however, if you plan to golf with the watch at all, the vivoactive 3 wins since it tracks golf. You can download courses directly from Garmin Connect and get all sorts of golf-specific stats, including distance to the front, middle, and back of the green.
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Conclusion – Garmin vivoactive 3 vs Forerunner 645 Music
The 645 should be reserved for extra serious runners or people (like myself) that are enamored with the idea of phone-free workouts. Otherwise, it’s simply too expensive, despite being a really good GPS sport watch. In most cases, the vivoactive 3 will do just fine. It’s a sport watch, heart rate monitor, activity tracker, and smartwatch.