A faster half marathon – Last long run and more speed work A faster half marathon – Last long run and more speed work
A faster half marathon – Last long run and more speed work
A faster half marathon – Last long run and more speed work
A faster half marathon – Speed repeats and sunrise runs A faster half marathon – Speed repeats and sunrise runs
A faster half marathon – Speed repeats and sunrise runs
A faster half marathon – Speed repeats and sunrise runs
A faster half marathon – Back to training, resuming the Garmin Coach plan A faster half marathon – Back to training, resuming the Garmin Coach plan
A faster half marathon – Back to training, resuming the Garmin Coach plan
A faster half marathon – Back to training, resuming the Garmin Coach plan
Best Garmin watches for running Best Garmin watches for running
Best Garmin watches for running
Best Garmin watches for running
A faster half marathon – More speed work and pausing the Coach plan A faster half marathon – More speed work and pausing the Coach plan
A faster half marathon – More speed work and pausing the Coach plan
A faster half marathon – More speed work and pausing the Coach plan

Deciding between Garmin Forerunner 245 and 645

How does the newly released Garmin Forerunner 245 compare to the older Forerunner 645? That’s the question I asked myself when I went looking for a new watch and this article will guide you through my findings. 

For the past few months I’ve been thinking about replacing my Garmin Vivoactive 3. The touchscreen had started to bug me, I can’t count the amount of times I accidentally pressed something on that screen. And, I was interested in more running data. The Vivoactive 3 provides basic data, but the more I was running the more I got interested in performance data. I am very satisfied with Garmin in general and since I’ve also started the Garmin Coach half marathon plan, I have not considered other brands. 

What am I looking for in a new watch?

    • All the basics the Vivoactive 3 has: GPS, heart rate, etc.
    • Advanced running data
    • Suitable for every day use
    • Music

The most complete option at the time would be the Fenix 5S Plus. It looks awesome, has everything I could need and more. But, it also has a price tag of about € 650,- and that is a little more as I’m willing to spend.

In the back of my mind the decision was already made, the Garmin Forerunner 645 Music has everything I want and it looks almost identical to the Vivoactive 3, which is a plus point in my mind. It has more advanced running statistics, and: it has buttons instead of a touchscreen. Done deal! But then Garmin went ahead and announced three new watches: Forerunner 45Forerunner 245 or 245 Music and the Forerunner 945. The Forerunner 245 Music and the 645 Music are similar in features and price, so I had a dilemma to solve.

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Garmin Forerunner 245: $ 300 (check the current price on Amazon)
Garmin Forerunner 245 Music: $ 350 (check the current price on Amazon)
Garmin Forerunner 645: $ 280 (check the current price on Amazon)
Garmin Forerunner 645 Music: $ 350 (check the current price on Amazon)

Fitness features

Both the Forerunner 245 Music and the 645 Music are equipped with a LOT of awesome features. Find and compare them for yourself one the Garmin website: 245M and 645M.

The 645 tracks 19 different sport profiles and the 245 only 16. There are some differences in the profiles, but the main thing the 645 has that the 245 doesn’t is: skiing, snowboarding, XC skiing and stand up paddle boarding.

Forerunner 645 (Music)
Barometric altimeter. More accurate elevation tracking as well as stair climbing.
Lactate Threshold. The estimated level of effort or pace (only when paired with a chest heart rate monitor).

Strava Live Segments. Notifications on your watch when you approach segments of interest (Strava Summit required).

Forerunner 245 (Music)

Pulse OX. Wrist-based pulse oximeter to gauge the saturation of oxygen in your blood. Knowing your oxygen saturation can help you determine how your body is adapting to exercise and stress.
Firstbeat race predictor. Improved race time predictions. While the 645 uses VO2Max only to predict your race times for 5K, 10K, half and full marathon, the 245 also takes long- and short-term trends in your weekly running mileage totals into account.

Update 11-01-2020
At the end of 2019 a new feature was rolled out to the Forerunner 245: PacePro. It’s an interesting feature that will help you with pacing during your race. You are able to set up your race strategy in the Garmin Connect and in combination with Garmin Courses it can even factor in elevation. During your race your watch will show your target pace for each split and how you are performing compared to the target you’ve set. 
This feature will not be available on the Garmin Forerunner 645. 

Battery life

The battery life in smartwatch mode or GPS mode with music doesn’t vary much between the two watches, but the GPS mode without music does show a big difference. The 245 will give 10 hours longer battery life with GPS and without music.

Forerunner 645 (Music)

Smartwatch Mode: Up to 7 days
GPS mode with music: Up to 5 hours
GPS mode without music: Up to 14 hours

Forerunner 245 (Music)

Smartwatch Mode: Up to 7 days
GPS mode with music: Up to 6 hours
GPS mode without music: Up to 24 hours

Smart features

Garmin Pay is only available on the Forerunner 645. This allows you to make payments without bringing a card, phone or cash. Availability depends on location and banks compatibility.
Assistance alert and crash detection are only available on the Forerunner 245. This will automatically send an alert to selected contacts when your watch detects a fall or it can be activated manually with a button press.


The design of both watches is similar. Both have a circular design, but while both watches have a bezel, they are not made of the same material. The 645 has a stainless steel bezel available in different colors, while the 245 has a bezel made of fiber-reinforced polymer, available only in black. 

Each watch comes with Corning Gorilla Glass 3 and a 20 mm silicone quick release watchband. 

Size and weight Forerunner 645 Music: 42.5 x 42.5 x 13.5 mm / 42,2g
Size and weight Forerunner 245 Music: 42.3 x 42.3 x 12.2 mm / 38,5g

While the Forerunner 645 is available with different color bezels, the watch itself is always black. The Forerunner 245 always has a black bezel, but the watch itself comes in either black or white. Both watches can be ordered with different color watchbands as well. 


For me there wasn’t one feature that the other watch was missing that I really needed or wanted. Based on all this data, I couldn’t make a decision. Both watches are very complete for both running, other sports and every day life. So, I made looks the deciding factor. I went to a Garmin store that has all Garmin watches on display to touch and play around with and I went with the watch that looked and felt the best in my opinion. The Forerunner 645 Music has been in my possession for two weeks at the time of writing this and I have no regrets. It is a great watch. I’m sure I wouldn’t have thought differently if I had gotten the Forerunner 245 Music though. Whether you should buy the 645 or the 245 all comes down to personal taste, and my taste went with the Forerunner 645 Music.
Update 11-01-2020

Knowing what I know now I would probably have chosen the Forerunner 245. Partially because of the addition of the PacePro feature, partly because this is a sign the Forerunner 645 is no longer getting any new features, while the Forerunner 245 will probably receive more cool, new features. 

26 thoughts on “Deciding between Garmin Forerunner 245 and 645”

  1. Thanks for your review. I’m debating whether to get the 645 v the 245. I’m currently using the Garmin Fenix 3. Works well, but is becoming a bit laggy, and l want to future proof my next watch. Intrigued by the body battery and the Ox pulse thing, but like the idea of Garmin pay, and an altimeter. Still not sure, but you’re well written review has given me something to think of.

    1. Hi Derrick! Thank you, I’m glad it helped you. I should actually update this article. The 245 got a new feature recently that does not appear to be coming to the 645: PacePro. Interesting feature you should look into. And who knows what else might still come. I don’t regret buying the 645, but knowing what I know now, I would’ve picked the 245! It’s more future proof.

  2. Thanks for your response. Just checked out Pace Pro. Looks like a great feature. I think I’ll be getting the Garmin forerunner 245. Now to decide if l want the music or non music version.

    1. Can’t help you there! I personally barely use the music function as I usually have my phone with me. I got the music version mainly because it was a great deal at the time. Good luck with your decision!

  3. Decided on the non-music version of the Garmin forerunner 245. Not a huge lover of music when l run. Excited to order it later this week. Thanks again for a great informative post.

  4. Hi,
    Thanks for your article of comparing 645 and 245. Very helpful read as I am deciding which one to buy.
    Today I got a deal alert from Amazon for 645 which is cheaper than 245 and thought it was a great deal.
    But after doing some research, I found out 645 is using older technology than 245.
    Most likely I will pick 245 as I am not interested using Garmin pay and PacePro feature sounds very interesting.

    For earphone while running outdoor, I highly recommend AfterShokz since you can hear road noise and music at the same time, lightweight, waterproof, and most of all, no ear pressure each time you land your feet on the ground.

  5. Nice review.
    I have question about FR 245 in running track on cloudy days, my Strava connection have FR 245, and when he run on that condition, the GPS create circular pattern outside the track.
    In short, does FR 245 has GPS issue?

    1. Thanks! There are a lot of factors that can influence GPS accuracy. Cloudy weather, tree coverage, tall buildings, etc. It could be helpful to check the GPS settings and add Galileo or Glonass. I haven’t heard about GPS issues on the 245, but since I bought the 645, I can’t speak from personal experience.

  6. Hi, I wonder if either one gets Lactate Threshold Guided Test, because I can’t find it on my 245 Music. Is it just mine or not

    1. Hi! On my 645 it’s an option when you select your run activity and go to settings, then training. I think it’s not available on the 245 though. You’ll also need a chest strap for it to work.

  7. I’ve been going back and forth a garmin store for the past month to know the difference between the 645M and 245M. The store manager can’t give me a full explanation. Your well written and detailed article did, thank you so much for that. I have decided to get the 245. Three reasons: 1) its lighter 2) it has pace pro ( interesting addition ) 3) i have no use for garmin pay. Will update here as soon as i receive my forerunner 245 music.

  8. Larissa Farinazo

    That is exactly my dilemma right now. FR245 is amazing, new model, new sensor etc.. but it is not as beautiful as the FR645. I will be wearing it all day as my “smart” watch, so Id like a more premium look. If the FR245 had metal bezel it’d be the Perfect watch. I can’t decide. Ive been debating about this for 2 weeks now. It is killing me. I am even thinking about Vivoactive 4, but I don’t like the touch screen as well. I started running last year, but I want a watch that helps me to improve. Ughr. Help please.

    1. I fully understand your dilemma. The main thing with the 645 is that it has older hardware and will not be getting any new features. I’m looking at the Fenix 6, but can’t justify the price. I’ve heard rumors on a 655 coming out, but that’s taking already longer as expected.

  9. This helps me decide between the two. I was leaning towards the 645 but not am considering the 245 based on your feedback. Thanks.

  10. Trying to decide between the 245 & 245M, don’t listen to music much but the 245M has WiFi which enables auto uploading of data and downloading of software updates. I also read that since the 245M has more storage space it will enable other updates in the futrue that the 245 wont get..

  11. Your article helps a lot indeed. I have studied for weeks the difference between the 245 and 645. I once decided on 645M because there was a cheaper price. But your information of pace pro attracts me. For the time being, pace pro sounds more attractive for me than the LT. Will decide this week. But do you think the GPS and heart rate data are correct In 645M? There are still many comments on these at the forum. Thanks.

    1. Hi Peter. HR and GPS was accurate enough for me on the 645, no issues. In general the 245 is build with newer technology though and it will be receiving software updates that won’t go to the 645. Good luck with your decision!

  12. I read the Youtube reviews and blogs before buying a 245M. At the time it was cheaper by £10 than the 245 when bought direct from Garmin and a good bit cheaper than the likes of Amazon (Garmin sale ended yesterday). I thought the music would be good company for running and the WiFi would help with connectivity e.g. loading songs and updates etc. The 45, 45 Plus also seem to do everything I might want when starting out, but 245 and 245M get good write-ups so perhaps I’m missing something? 645M seems to be not consistent with the 45 line-up of 45, 245, 645 and 945 as the sensor (to me) looks different and perhaps it is a sign it is from the previous generation too?

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