Different Calorie calculations for Garmin vs. Strava

My Garnin 510 shows i burned 1036 yesterday but Strava is showing 1703 (which is wrong... Any idea? ) happening every time

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78 comments
  • Official comment

    Hello all,

    I know this discussion has been going on for quite some time. Thanks for all those who have contributed and left comments already. 

    We've put together a survey to help us document the feedback we're receiving about Strava's calorie calculations. Please take a moment to fill it out with recent examples. We appreciate the help! 

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  • Hi Derek,

    We use a different, 'old fashioned' method of calculating calories on Strava, which requires estimating power output, in Kilojoules, then factoring in human inefficiency on the bike (about 26%).

    Garmin's calorie estimations mainly use HR data and are generally on the high side. We calculate estimated power and calories using a lot more data inputs. For more information, see this page:

    https://strava.zendesk.com/entries/20959327-Calorie-Calculation

    To get both power and calories as accurate as possible, make sure you have an accurate weight and type entered for your bike, as well as your own body weight. Make sure you include weight for clothes (helmet, shoes etc.)

    You might be interested in this article about the accuracy of Garmin estimated calories.
    http://www.dcrainmaker.com/2010/11/how-calorie-measurement-works-on-garmin.html

    Please let me know if you have any additional questions.

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  • Hi Elle,

    Will Strava use HR data provided by connected HR strap to calculate calories more accurately?

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  • Hi Elle, 

    I have the same question as Vitaliy.  I also see big differences across tools and curious to compare them.  I use  heart rate monitor and wonder if Strava takes that into account.

     

    Thanks!

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  • Sorry Vitaliy and Peter - Strava does not use HR data to calculate calories at this time. We stand by the accuracy of our methods of calculation! However, afterall, all calorie calculations are just estimates. 

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  • Elle, thank you for your prompt reply.  One dilemma I have is what calorie calculation should I accept for biking: the one from iSmoothrun that I equally respect that takes into account HR or Strava that does not. Interestingly in case of cycling the difference is almost 100%, i.e. iSmoothrun counts almost double the calories of Strava.  I know you stand for your calculations, just like the iSmoothrun developer.  At you are right: these are estimated.  Maybe the bottom line is: just do it and enjoy, more important than actual calories!  (Maybe except when you are on a tough diet or weight reduction program. :))

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  • I agree it's a tough dilemma with many variations on how to calculate calories! Sorry we can't offer more options at this time. 

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  • After my last run my HRM showed 421 cal. I checked several online calculators - ranged from 415 to 440 cal. Strava - 1,107. Am I missing something?

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  • Sorry Laika - it looks like we don't use heart rate data to calculate calories for Runs either. Our documentation states:

    "Calorie calculations for runs require that you enter your weight.  Strava will use your weight and the elevation data and distance of your run to estimate calories burned. If you're having trouble getting calories calculated for your Runs, check or reset your elevation correction by following the instructions on Elevation Correction for your Activities. Calories for runs are a function of speed (grade adjusted), weight, and moving time. Multiply these together with a scaling factor, and that's the estimate."

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  • I use iCardio DigiFit and a HRM for accurately tracking my workout stats and import my workout into Strava. My only grouse is that the calorie burn calculation gets overwritten by Strava's estimate. Would be great if Strava could provide calorie burn based on actual heart rate readings. There are a few popular formulae and are all free to use. HR readings over time as the basis of calorie burn is a much better estimate than the method Strava currently use. Alternatively, could Strava provide an edit option for users to manually correct the calorie burn reading (among others)?

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  • I know you do not use HR to calculate calories, but devices such as Garmin do use calories.  The HR monitor makes the calculations much more accurate.  When I do not have by HR monitor it will over calculate calories burned by 2x to 3x more than I actually burned.  Then when the Garmin data is uploaded to Strava, the calories on Strava will match that of the Garmin computer.

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  • I know this is an old topic but I'm experiencing more of similar issues with this. I bike using a Garmin computer and Garmin Heart Rate monitor. At the end of my ride, the calories calculated using my heart rate by the Garmin are very accurate. 

    I upload my data into Garmin Connect's website (my calories on the website match what my Garmin says) and then Strava sync's with the Garmin Connect website and instead of using those calories it calculates it on its own and is way off. For example a bike ride where I burned 250 calories, Strava will calculate it and say I only burned 140 calories.

    It's way off and very obvious especially if you use a heart rate monitor, which is one of the most accurate ways to calculate calories along with your weight.

    If calories are already included in the data on Garmin Connect, how come Strava doesn't use that data and calculates it again (and does a poor job of it honestly...)?

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  • I too use a Garmin 510 with HR and Strava can display wildly different calories - anywhere from 30% - 50% different.  The link on DC Rainmakers site (posted from Elle) suggests that the Firstbeat algorithm is one of the most accurate outside a lab (within 5-7%) and this is what is used by the 510.  So why can't we use this data in Strava?

    http://www.firstbeat.com/consumers/garmin-heart-rate-monitors

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  • I'm 48 and weigh in 234lbs, getting back into cycling after 20 or so years. Yesterday I did a 25 mile ride with 700ft of elevation gain at an average speed of 12.8mph, fairly strenuous for me at my fitness level, and was wearing a HRM. Garmin says I used 1330 calories, Strava says 700. I'm going to go out on a limb here and say the Strava number is wronger than the Garmin number.

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  • I'm currently using Zwift quite a lot (for my cycling) and Zwift automatically uploads the ride onto Strava.  A one hour ride at an average of 236 watts and I'm 82 kg comes out at 800 KJ - i.e. 200 calories - never!  Surely this can't be right?

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  • "We stand by the accuracy of our methods of calculation! However, afterall, all calorie calculations are just estimates."  Is a pretty obnoxious response honestly.  "All estimations are just estimations, so it doesn't matter how much less accurate our estimation is than anyone else's" seems to be what you're saying.  You might as well publish random numbers if you don't care how accurate your estimates are.  Striver's numbers are pretty much just as worthless, so why bother.

    When you factor in "human inefficiency on the bike (about 26%)", that explains exactly why Strava calculations are less accurate than everyone else's.  Human inefficiency depends on physical conditioning of the human in question, so it is not a constant.  Factoring in heart rate is what helps more accurately determine the amount of work being done, because it indicates the fitness capacity of the human.  If two people do the same ride, with one's average heart rate at 180bpm, and the other's at 160bpm, it is clear that the person averaging 180bpm is using more effort to accomplish the same amount of work.

    So Strava measures the amount of work being done, and Garmin measures the effort of the human doing the work.  Both are relevant, but to varying degrees.  Strava's estimate is useful for comparing the difficultly of one segment against another, but Garmin's is more useful for guiding the fitness of the athletes.  I can tell you I only care about the second number, Strava's number is useless to me, and probably less relevant over all for the most common use cases.

    You might stand by your poor estimates, but they're still very misleading when used to represent something different than what other's use the same name to describe.

    It's very frustrating to see wildly different calorie counts in Strava.  At least rename the field description if you're not going to use the best available data to deliver better estimates for calorie count.

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  • I only want to know how much I can eat and not gain weight. My imperial data says I can not eat the calories garmin calculates and the strava amount is the more reasonable extra amount I ca consume. This is the bottom line to me.
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  • Just wondering why Strava tends to add ~10% to the kJ in order to calculate calories?  Usually kJ is roughly equivalent to calories burned (when using a powermeter obviously, not estimated power) as there are ~4 kJ in a (kilo)calorie, and humans tend to be ~25% efficient.  But for some reason on my cycling files Strava likes to give me an extra 100 calories per 1000kJ, why is that Ellie?

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  • I think for people who obviously care about head things being accurate and have gone out and bought peripherals that deliver what are obviously more accurate numbers to (Fitbit, basis peak, garmin, etc.) star a should really be importing these numbers into their app, I mean why bother communicating with the device if you are not using all that information in the best way possible?  Who cares about my "suffer score" just give me the real fitness information I am looking for.

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  • If you are using calories as part of diet control and need to consider how many you have burnt in order to calculate your intake, then use Strava figures and you will lose it quicker, because you will put less back in.

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  • @Ian Berry What about me? I'm plenty thin enough (8% fat), but I often struggle to refuel, and like to know calories to support my fairly intense training.

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  • I'm getting the same issue: I did a 50 mile, 3.5 hour ride on Sunday and my Garmin Edge 500 with HRM says I burned 2188 calories. Strava reckons the same ride used 1252 calories.  My weight and the weight of my bike are entered accurately into both, as is my age (46).

    One interesting point that someone made on here recently is about Strava taking away the inefficiency on the bike (about 26%).  Quite correctly, the poster raising this points out that this calculation is completely irrelevant and Strava are completely and utterly wrong about this.  Strava's calculation seems to only measure the amount of work converted into forward motion, which is a very simplistic and not difficult to calculate energy equation.  Of far more relevance for all athletes is the amount of actual work they have done, because if your aim is to lose weight, or even if it's not, you should be more concerned about the amount of energy your body has burned, which then gives a guide as to how much food you should be consuming, either to maintain weight loss or if weight isn't your issue, to make sure that enough food is consumed to replace what has been burned, preventing muscle consumption, which the body does in lean individuals with no body fat to use as fuel, reversing any gains made.

    For me, Strava should be converting Garmin data as is, with the calorie count that Garmin give, perhaps then using their own numbers as an "Efficiency on the bike" percentage, which would be very useful, comparing the calories burned by the body with the energy used to propel the bike.

     

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  • For me personally, the Strava calorie estimate is way off. It typically comes in at about 60% of what I actually burn. It's tough to figure out which calculator to use. Then only way to zero in on accuracy is to stick with one calculator and see the results on the scale. Weigh yourself at the same time every week and find your margin of error.

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  • Adding my comment to this thread. Same thing here, my Garmin Edge (paired with Garmin HRM) reported 838 calories for my bike ride today, but Strava reported it as 425. Based on my effort involved today, I am pretty sure I burnt closer to what Garmin reported. My heart rate was consistently in the 145-150 range, most of the ride, which is fairly on the higher side for me and I could feel the effort and it was not a leisurely ride. 

    I wish they would at least show both the device reported number and their own calculated number in the Strava dashboard. 

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  • I have similar issues with very different calorie estimates on garmin and strava but the difference being that my garmin estimates are much lower than strava. This applies across all disciplines. Run tonight: garmin calorie estimate - 569, strava - 782. Bike yesterday, garmin - 1266, strava - 1565.
    I wonder why strava seems to over estimate for me but not for the majority of people?

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  • I believe Strava Calorie Calculation is not correct, I have my HR Monitor Strap paired with my Garmin tracker and my phone (using Strava) 

    I did a Hike yesterday, almost 800 meter elevation in 50 min, 2.2 KM. Garmin shows 890 Cal, Strava shows 290 ! I understand based on reading this thread they dont match, but there is absolutely no way, climbing that mountain is going to be only 290 ! 

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  • Just checked my Fenix vs. Strava numbers. The Garmin is always 61% of the Strava number. Interesting I thought the numbers would be different. For me it looks like the Strava algorithm is always higher by the same percentage. I wish we could just use the Garmin calorie counts or have it be user selectable. 

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  • I did 2 10K runs this week and Strava's calories number are around 20% higher then my Garmin connect. I run with my Fenix 3 HR and have Garmin connect sync data to Strava. Why can't Strava just take the calories numbers from Garmin instead of changing it?

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  • I rode 60 miles in 4 hours.  Garmin Edge 1000 with heart rate monitor, speed and cadence sensors reports 3516 calories, however, after the sync Strava on reports 1691 calories.  Strava, there is simply no way your calculation is correct.

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