Strava over-estimates Calories

Does anyone else notice that the calorie info on Strava is a huge overestimate from the amount of calories you actually burn?  Sometimes the estimated calories burned on Strava after I upload my ride is 2 to even over 3 times what I actually burned.  What algorithm is used and why is there such a discrepancy?  

Today alone I did a ride where I only burned 1,500 kcal according to my Garmin computer (which is actually really about 800 additional calories burned over my basal rate.)  Strava states I burned 3,100 kcal.  My Garmin 810 with all of my personal info, HR data, VO2 Max, FTP, etc I know is much more accurate.  

How could Strava possibly calculate anyone who rides for only 45 miles stayed in Z2 70% of the time, Z3 15%, and Z4 for only 1% could possibly burn over 3,000 calories?  I know it is not accurate, but there are people who do depend on this as their only means of calculating calories burned.  Without a HR monitor it exaggerates even more.  It would have indicated that I burned well over 4,000 calories, when I actually burned less than 1,000. 

BTW, when the ride is uploaded on GarminConnect, the calories info is the same as that on my bike computer.

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  • Official comment

    Hi Folks, 

    Earlier last month, we updated our calorie calculations to use the number of calories burned recorded in .FIT and .TCX files instead of our default calorie calculation. If your device records in either of those files, then you'll see those numbers on your Strava activity. 

    You can read the announcement here

  • To see the difference here is today's fairly easy ride posted on Garmin: https://connect.garmin.com/modern/activity/1238251609

    Here is the same ride posted on Strava: https://www.strava.com/activities/627730708

  • My running stats (with HRM) are ridiculous when synching from Garmin->Strava.

    Its a massive pain as I'm losing weight and I used to use Strava to synch to myfitnesspal (because the local pool "swimtag" only synchs to strava). But I can't any more because of this. It was fine until a few months ago and I get the same issue using two different watches.

    How much out - try 400 cals in Connect being translated as 5000 (yes thousand) in Strava:

     

    3.2 mile run:

    5865 in Stava (think that may kill me!)

    https://www.strava.com/activities/631917078

    369 (about right) in Connect

    https://connect.garmin.com/modern/activity/1243751937

  • Hi Jason and Simon,

    I've gone ahead and created a support ticket for both of you.  It definitely shouldn't be showing that many calories, so I'm having our support team look into it for you.  Thanks for letting us know.

    -Shelby

  • I received feed-back from your staff and it is really appreciated.  I understand the algorithm you are using to calculate calories and I also understand the issues with all the different ways it is calculated, including issues with Garmin itself.

    The fact that the Garmin device may have issues does not mean the calculation formula you are using is any more accurate.  I realize it varies from person to person, but for me, I can tell you it is way off.  All of the data on both Strava and my computer are the same, weight, age, equipment, etc.  So the variables are what is used to do the calculations and how it is calculated.  

    One recent ride on flat ground where I was putting around with my wife and my HR never got out of zone 1 for example, Strava stated that I burned over 1,600 kcals on a 45 minute easy paced ride.  I actually burned about 300 kcals (actually only 100 over my basal rate.)  Strava overestimated my calories by multiple of over 5.  Yes, over 5 times what I actually burned.  

  • Today I decided to test out the accuracy of Stava's calorie calculations.  I intentionally went for a moderate paced short distance ride with very little climbing.  

    Under 30 miles (short ride for me)
    Averaged about 18 mph (very moderate pace for me)
    2,400 ft of climbing (not very much climbing at all)
    All grades were under 10%
    Heart rate never got above zone 4 (it was only in zone 4 for 7% of the time), Heart rate was in zone 1 and 2 for over 60% of the time
    Only out for 1.5 hours.  

    Given this information there is not possible way I burned over 1,000 kcals. According to my computer, I burned a little over 700 kcal.  This is probably pretty accurate considering the little effort I put in, the little time I was out, the the ease of the ride.  

    According to Strava I burned almost twice that, over 1,300 kcal.  I can say for certain that the formula Strava uses to calculate calories is not very accurate at all.  This is a way overestimate.  And I can also tell you that the times I forgot my HR monitor or my HR monitor died, it would have doubled or tripled the value it calculates with my HR monitor.  

    Strava really needs to consider using a different formula for calculating calories.  There are people who depend on accurate information as they are trying to lose weight.  

  • BTW, here is the ride on Strava: https://www.strava.com/activities/638679011

    Here is the same ride on Garmin: https://connect.garmin.com/modern/activity/1253031885

    And to show you it was a moderate pace ride for me where I did not even put in a full effort, you can see that there are no PRs and nothing close to any personal bests for me on any segments of this ride.  I have done these routes hundreds of times and hold the KOMs on some of the sections.  

  • Strava overestimates running calories too, especially when there is some elevation gain. As I understand the algorithm doesn't use HR data and relies mostly on grade adjusted pace and a few other metrics like athlete weight, time, etc. Strava's algorithm doesn't take athlete's efficiency into account.

  • I have been using Strava to track calories burnt and using myfitnesspal to track my calorie intake. Not being very up on the in and outs of how the calculations are undertaken I have been trusting Strava to provide me with the right information. 

    I have been religiously in my weight of food so I know my calorie intake in correct, however I am still failing to loss weight, the only conclusion I can come too is that Strava is incorrect. 

    I have been using runkeeper app along side Strava and like many people say the calories are much more inline with what the research I have undertaken would seem to suggesting I would be burning. 

    I am extremely disappointed with Strava as someone who is not a fitness professional and is using the app to get fit and loss weight I have found this at times a difficult process to understand what has been going so wrong. I have now canceled my Strava membership and will be moving to using another app. 

     

     

  • If you have a power meter, Strava will estimate your calorie burn as1.15 Calories -  4.7kj roughly - for every 1kj expended.  This assumes 21.5% human efficiency, whereas Garmin will assume about 23% human efficiency.  I find the Strava power based numbers work for me.

    Running is different.  Strava's running calories are consistently 30% high compared to numbers derived from studies where oxygen consumption was measured.  General rule of thumb:  70 Calories per 100 lbs body weight per mile.

    I complained about it on this forum.  One of their employees posted their algorithm.  I couldn't find it anywhere in the literature.  I have no idea where they get it from but it's pretty damned wrong.

    If Strava fixed their running calories I could hook it up to LoseIt and import it straight in.  Unfortunately I have to manually enter my rides from Strava and use LoseIt's far superior running calorie calculations for my runs.

  • I just posted this to support:

     

    This is a follow-up to your previous request #536488 "Re: Turn ridiculous calorie count off, or disconnect from HealthKit"

    Previously you had posted this formula for how you calculate calories:

    Average speed * 3.6 * weight * 3.413E-4 * moving time
    Where:
    Average speed = grade adjusted speed based in meters/second
    Moving time = in seconds and based on grade adjusted speed
    Weight = athlete weight in kg

    This breaks down to grade adjusted distance in meters * weight in kilograms * 0.00123 or
    Distance in km * weight in kg * 1.23 - 1.23 Calories per kg per km.

    The literature does not support this value.  The generally accepted figure is 0.97 Calories per kg per km.  Please correct this so that I can actually import your values into the calorie tracking app that I use.

    Sources:

    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1859586/pdf/brjsmed00270-0005.pdf

    http://www.runnersworld.com/weight-loss/how-many-calories-are-you-really-burning

    http://www.runnersworld.com/peak-performance/running-v-walking-how-many-calories-will-you-burn (an update)

    http://www.runnersworld.com/sweat-science/mythbusting-running-a-mile-always-burns-the-same-calories (getting into the weeds)

    and also from the Compendium of Physical Activities:

    https://sites.google.com/site/compendiumofphysicalactivities/Activity-Categories/running - work through the math and it agrees closely with the above articles.

  • Thanks for the comments about Run calories John - I'll make sure someone takes a look at your post. 

  • I've noticed a big difference in calories expended between my Garmin connected to a chest-strap Heart Rate Monitor and the Strava recording on my iPhone.  Did a little research and realized that the difference was the HRM. Just got a new Apple Watch, which I connected to Strava, and figured that the problem would be solved now that both devices have heart rate info.  Surprise!  Strava doesn't use heart rate info to calculate calories even if available!  Very disappointed.

     

    Why does it matter?  I have type 1 diabetes and have been trying to synch my daily exercise with my food intake on My Fitness Pal.  May switch back to Endomonda because of this.

  • I also notice that Strava seems to inflate calorie burn rate by about 15-30% compared to most online calculators. Strava's numbers are definitely an outlier.

  • I have found that Strava does not calculate enough. 40 mins of cycling w/o HRM)  @ 15.4mph and only burn 315?  Or the others just way over calculate.... Map My Ride said 968.

  • "I have found that Strava does not calculate enough. 40 mins of cycling w/o HRM)  @ 15.4mph and only burn 315?  Or the others just way over calculate.... Map My Ride said 968."

    Both are way overestimates.  You did not burn 315 calories in only 40 minutes, especially only going 15 mph.  Even if you are in poor shape and 15 mph is hard for you, that is still way to many calories.  Most likely only burned about 1/3 to 1/2 of that.  Map My Ride is ridiculously overdone.  


  • Dunno surely it depends on the gradient, the bike and also on the weight of the rider - 7 to 8 calories a min sounds OK to me, as you'd burn 3 cals a min just strolling around. 968 is ridiculous for sure though, lol

  • I'm new to Strava and I've also discovered that it seems like Strava underestimates my calories burned. If the  calories are not underestimated then there is absolutely no point in exercising. I rode for one hour last night at an average speed of 11 miles per hour. It said that I burned 180 calories. My problem with this is that I could sit at my desk all day and burn 122 calories per hour. If I stand, rather than sit, I go up to 163 burned per hour.

    How is it possible that all that huffing, puffing, sweating and wheezing only nets me about 17 more calories per hour? The calculations are wrong or this is very discouraging. 

  • Mapmyride calculates kj, you would need to convert it to kcal and then it gives a reasonable figure.

    It is so annoying that Strava is overestimating calories burned. I went for walk today and it says I burned 380 kcal in 1 hour. There's no way I burned that much, I am 59kg 159m and I'd have to sweat quite a bit to get 380 off.

    Common Strava get this fixed! This is no rocket science, there's so many resources out there to work out an appropriate formula!

  • Yes Strava there's something wrong here. I just went for a 3.7 mile walk at 3.4mph average speed (took me about an hour). I'm about 13.5 stone and it said I burnt 607 calories.

    However last week I went for a 15 mile ride and averaged 16mph. It said I burnt 563 calories.

    The ride was a lot of effort whereas the walk was easy! Go figure.

  • Just to add another voice (and another person with diabetes) my disappointment at the wild overestimate of running calories. I use my calorie counts to monitor and balance my medical condition as well as physical hralth, so need at least a reason we assurance of accuracy.

    I was excited for the social and challenge aspects of Strava, but this is a glaring (and fixable) error that means I will be switching back to my old running app.

  • One quick hack Kirsten - set your weight to 0.78 * your actual weight.  Now your calorie burn will be in the ballpark.

    @elle someone looked at my support post but no action has been taken.  I guess Strava is OK with being way off on its calorie calculations.

    I honestly don't know why all these companies have all these different numbers.  Calories burned running, walking and cycling is well established.  There are numerous studies using oxygen consumption that have resulted in well accepted formulas in exercise physiology.  Not using these formulae is just plain incompetence.

  • I'm having the opposite issue. Did I ride yesterday and strava said I burned 750 calories. Garmin connect (Edge 820) and every other formula I could find says I burned closer to 1600-2000 calories.

  • Are you using a power meter? 

    If so, how many kilojoules did it report?

    If not, was this a road ride or a MTB ride?  Without a power meter Strava will drastically under report calories for an off road ride.

    Take the number of calories reported by Garmin connect.  Divide by hours ridden to get Calories per hour.  Divide that number by 4.  That will be really close to your average watts.  Can you average those watts for the entire duration of the ride?  Consider that top level UCI pros will make 350 to 450 watts over a half hour "finishing climb" and can average 250 watts over 5 hours.  An average Cat 4 can make 4 watts / kg on a half hour climb and maybe 2.5 watts / kg over 5 hours.

  • I use strava to track the way to my office and back. To prevent that I "spam" strava with 2 boring rides a day, i press on pause when arriving at the office and restart when i ride home.

    It looks like stava or whatever crashed in the middle of the pause and strava began to record while sitting in the office, because now I have a (I try tro translate to english) "time in movement" of 2:44 hours instead of ~30 minutes:

    https://www.strava.com/activities/882808010

    And I burned ~2.300 kcal!  Man, that was nice! I immediately drank 10 beers at home to compensate that ;-)

    Perhaps this helps to find out why strava has such a huge gap between reality and calculated calories because it's really a extreme example.

     

  • +1 for John Vance's post from 12/16/16. Same issue here. I was hoping to rely on Strava on the Apple Watch as my only tracking method for casual morning runs (would have been so convenient), and having those numbers import to Lose It! Unfortunately, this is not an option because Strava inflates running calories by about 1/3. 

    In my experience, Strava inflates calories for running and deflates calories for riding (unless you use a power meter while riding). Do not rely on Strava for calorie tracking for either form of exercise if you actually care about accuracy. You'll get fat running or starve yourself riding. Heart rate data appears to have no impact whatsoever on the burn rate. This is rather ridiculous for a mature, established fitness app. One would think addressing this would be a top priority for their development team.

  • Strava way overestimates running calories for me by 20%+. For example, today I ran 3.4 miles on a fairly flat path in 31:10 (9:05 / mile pace) and it calculated 588 calories! These seem to be "vanity calories", sort of like vanity sizes in clothes. Every other online running calorie calculator shows in the 414 - 481 range. When will this be fixed?

    (Yes I have correctly entered my weight on my profile.)

  • I find this strange too, I recently cycled up a mountain on my road bike. Garmin states I burnt 2443 Calories while Strava states 1528 calories burnt... 

    https://www.strava.com/activities/898310701

    https://connect.garmin.com/modern/activity/1618147327

     

    Why is there such a massive difference in calories??

  • I have the same issue that Strava overestimates the calorie burn consistently versus my Polar V800. On this Monday's run, Polar calculates 639 calories for 10.50 km 6:09 avg pace. Strava (synced directly to it from Polar software) states 827 calories burned.

    The prior posters statements that it ignores heart rate data makes a lot of sense. HRM is a must to get any accuracy.

    Fortunately my Polar syncs directly to myfitnesspal and I'm slowly losing weight despite eating my full allowance of exercise calories based on the Polar stats. I'm already lean but want to drop 8 lbs before my race May 7th to improve my results. I've researched it and the Polar stats appear to be some of the most accurate out there. Many apps overestimate the exercise calorie burn. Definitely ignore any estimates that aren't based on heart rate.

    https://flow.polar.com/training/analysis/1216277134

    https://www.strava.com/activities/908077354/overview

  • Just went for a 1-hour walk. Garmin says 564 calories (reasonable given my weight), but Strava says 837 (∆37%), which cannot be right -- no way I was exerting that much. When I checked on a 3rd-party site using weight, distance and pace, estimated calories burned was 607.

    Cycling, however, seems right on. On a 50k ride last weekend, Strava was 2255 Cal and Garmin was 2137 (∆5%). On a 26k ride before that, Strava 1244 vs Garmin 1398 (∆12%).

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