Gps watch vs phone app: Hi all, I did w8r... - Couch to 5K

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Gps watch vs phone app


Hi all,

I did w8r3 today with my neighbour’s gps watch on rather than tracking just with Runkeeper on my phone. The result was pretty depressing. According to my phone, I ran 5.85km in 35 minutes. According to her gps watch, I ran 4.6km in 35 minutes. 😢 Has anyone had this issue? Should I try using a different app?

17 Replies

My runkeeper on my phone does seem dodgy

I think it's maybe down to the hardware rather than the app itself

What I do is "fix the gps" route thingy on runkeeper and see what it says, for example, sometimes it drops my run down by up to 2km. This is the lowest possible, so I assume that my "real" distance is somewhere in between. Nothing is 100% accurate.


When I used both (a watch and runkeeper on phone), they were usually much the same with the results.


Just looked at one of my runs to compare. My phone automatically picks up if I walk or run. On a matched run my watch said I ran for 32 minutes and my phone said 37 minutes. The watch has GPS and obviously is started and stopped. So I believe my watch is more accurate 😊

Maybe try Strava and see if that's more accurate as that is what I use to use


I spoke to Garmin support about this a couple of weeks ago as my parkruns are consistently short on my watch and I had just completed a 5 mile guided run on Nike Run Club (iPhone 7plus) that measured nearly half a mile short on the watch. Here’s the gist of what they said:

1/ iPhones 4s (and above) have very similar specs of GPSr chips to their watches. They should in theory, therefore, read almost exactly the same distance in airplane mode.

2/ Mobile phones also gather location information from the cellular network, and the combination of that and the GPSr will always be more accurate than GPS alone.

So basically, my phone is going to be more accurate than my watch most of the time... which begs the question as to why Garmin don’t use the phone’s location services when the devices are connected.

Interestingly the iPhone 5s beat all but one watch in these tests and newer generations of iPhone have better accuracy, allegedly.

You can get a footpod for most running watches that elevates them to the top of the accuracy league, as it isn’t reliant on GPS then.

I’m unable to comment on the accuracy of any android devices, and there’s no doubt a few different GPSr chips used across the vast range of them.


Have you measured the distance using Google Maps?

jlegGraduate in reply to John_W

i take quite a roundabout route so it wouldn't be easy!

John_WAmbassador in reply to jleg

it shouldn't matter - you should still be able to measure it manually using Google Map's Measure Distance feature (right-click of the mouse!)

jlegGraduate in reply to John_W

Thanks for the tip. I just did it (twice) and the GPS watch is right :(

John_WAmbassador in reply to jleg

Ooops, sorry to hear that but Google Maps is my gold standard for such things. Navigate to an athletics track and measure it ... should be v close to 400m ;-)

I used to track my walks (keen hiker) on an iPhone 5s which in my case consistently overestimated distance by 20% until last years iOS release when it became much more accurate. I broke that iPhone this year, and replaced it with an iPhone SE which consistently underestimates distance by 20%. Wishing for something more accurate was part of my motivation for buying a Garmin Forerunner 235 gps watch, which at least in my case, has proven to be quite accurate so far. ( I don't bother turning on dual GPS - which it supports).

Adding a clarification - I was relying on the Health app provided by Apple when trying to measure distance on my phone.

I found this around Week 6 and I was gutted! I started using Strava and I do measure distances with google maps, both of those are in agreement. I know it's pretty miserable finding out, but at least you now know the truth. And 4.6k in 35 minutes is pretty good,whatever the distance you can run for 35 minutes which is amazing! 😊

jlegGraduate in reply to FatterPenguin

I'm fairly raging :D

I will go to 5km tomorrow with my neighbour and her watch!

FatterPenguinGraduate in reply to jleg

Believe you me when I found out my phone had been misleading me I was ready to sue the phone company for being big fat liars....

jlegGraduate in reply to FatterPenguin

W9r1 today: 5km in 35m recorded on my neighbours watch (strava and Runkeeper both say 5.4 in 35). It is done for sure now! 😆

FatterPenguinGraduate in reply to jleg

Excellent time! Well done you 😊


my garmin10 and strava are always the same and also correct at pr.


I have an iphone 7 (I think) so I think runkeeper is to blame here. It's true that when I look at the map the lines are always slightly off the street I know I was running on. When I correct it, it gets worse :/

I'll give strava a try tomorrow and see if it's more accurate. It's a shame though, I started out on a C25K app and switched to runkeeper when the free guided runs were over. Since then I've been tracking it all (albeit incorrectly it seems) with runkeeper and I liked being able to see the history...

At least I can see I've made progress between weeks 3 and 8 even if it's not the progress I thought it was :)

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