# Strava - how accurate is the calorie counter



## Mike J (10 Jun 2014)

Hi

I'm relatively new to cycling and have recently been using my road bike for commuting. 

I currently use Strava and was wondering if anyone has any idea how accurate the calorie calculation is. I don't expect it is precise by any means but how reliable is it? For example surely it won't know if I'm freewheeling or peddling down hills? Please forgive my ignorance or noobishness


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## MikeW-71 (10 Jun 2014)

Absolutely no idea. It will be calculated much like their power figures, so it's probably nowhere near. A rough estimate at best.


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## vickster (10 Jun 2014)

Not really but far better than garmin

30-40 cals per mile is a decent rule of thumb depending on your physique, speed and terrain


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## Hip Priest (10 Jun 2014)

It'll just be a rough estimate based on a few calculations.


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## Joshua Plumtree (11 Jun 2014)

I alway work on the assumption that I'm burning between 400-500 calories per hour, and then I remember I'm not actually cycling!


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## HLaB (11 Jun 2014)

Whist still not 100% accurate, I believe it is slightly more accurate if you have a HR strap/monitor. Never really bothered about it my self but I'm pretty sure that RWGPS, Garmin Connect and Strava all give different results from the gps track.


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## burndust (11 Jun 2014)

you'll always get better results with an HRM tbh, but in my experience with strava it does over estimate...but like others have said not as much as a garmin with the HRM...those readings are just silly tbh


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## HorTs (11 Jun 2014)

Again, I'm not sure how accurate it is but it seems realistic. Just make sure you have your profile complete - height, weight, age etc.


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## Cold (11 Jun 2014)

Are any of them correct I just had a look at my last ride and found the following

Strava - 3hrs 33 mins at 24.5k average was 1925 Calories
Mapmyride -3hrs 33 mins at 24.5k average was 3779 Calories


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## fossyant (11 Jun 2014)

Don't get tied up about it. Work on 800 or so per hour if you are riding hard.


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## ianrauk (11 Jun 2014)

Colderuk said:


> Are any of them correct I just had a look at my last ride and found the following
> 
> Strava - 3hrs 33 mins at 24.5k average was 1925 Calories
> Mapmyride -3hrs 33 mins at 24.5k average was 3779 Calories




None of them are correct. It's all guesswork.


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## vickster (11 Jun 2014)

Strava might be closer on my 30-40 cals per mile. MMR is nonsense unless you are very heavy and were only climbing hills on a fixie. What was average speed?


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## Cold (11 Jun 2014)

vickster said:


> Strava might be closer on my 30-40 cals per mile. MMR is nonsense unless you are very heavy and were only climbing hills on a fixie. What was average speed?


 
The average was 24.5 kph I only did one hill and weight 13 st 7 I don't take any notice of the calories but if some one was using them to lose weight they would be useless.


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## vickster (11 Jun 2014)

Ok misread, I do t work in kms, so how far did you ride in miles, then multiply by 30


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## Cold (11 Jun 2014)

vickster said:


> Ok misread, I do t work in kms, so how far did you ride in miles, then multiply by 30



1640 calories so Strava is not to far out with their calculations.


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## vickster (11 Jun 2014)

Which is what I said...however major pinch of salt with guesstimate


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## SatNavSaysStraightOn (11 Jun 2014)

and then you have to work out if they are taking this as above and beyond your average 2,000 calories (female) 2,500 calories (for a man) or whether they are taking it into account - which probably explains some of the difference between garmin calories and strava calories... personally I prefer to work on the additional calories to my usually daily limit rather than taking my daily calories into account... (and if that does not have you confused, nothing will!)


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## Rob3rt (11 Jun 2014)

SatNavSaysStraightOn said:


> and then you have to work out if they are taking this as above and beyond your average 2,000 calories (female) 2,500 calories (for a man) or whether they are taking it into account - which probably explains some of the difference between garmin calories and strava calories... personally I prefer to work on the additional calories to my usually daily limit rather than taking my daily calories into account... (and if that does not have you confused, nothing will!)



eh....


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## SatNavSaysStraightOn (11 Jun 2014)

Rob3rt said:


> eh....


normal daily calories needed for every day life 2,000 for a woman, 2,500 for a man. Exercise uses extra calories in addition to that daily figure.

Garmin figures are always way over what strava or anything else seems to predict.

So is strava saying you have used an extra xyz calories in addition to your daily usage or does that figure include your daily calories...

so
exercise calories + 2000 (or 2500) = what you have expended over the course of that day
or
exercise calories for the hours you exercised to include standing calories for those hours as well (say 4 hours) + 20/24 of 2000 (or 2500 standing calories minus 4 hours of the day) = total energy expended over 24 hours assuming 4 hours of cycling...

just a random thought


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## Rob3rt (11 Jun 2014)

It is saying how many calories they think you have burnt during the activity you have just uploaded. That's it, nothing more, nothing less.


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## fossyant (11 Jun 2014)

Rob3rt said:


> It is saying how many calories they think you have burnt during the activity you have just uploaded. That's it, nothing more, nothing less.


 
Agree, it's just 'rubbish'. There. Keep riding folks !!


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## SatNavSaysStraightOn (11 Jun 2014)

Rob3rt said:


> It is saying how many calories they think you have burnt during the activity you have just uploaded. That's it, nothing more, nothing less.


so that should, in theory, take into account a proportion of your 'daily calories' then... to hold a constant body weight...


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## Rob3rt (11 Jun 2014)

SatNavSaysStraightOn said:


> so that should, in theory, take into account a proportion of your 'daily calories' then... to hold a constant body weight...



You are over complicating it.

As I said above, it is guessing how many calories burnt during that activity, nothing else. What you burnt during the rest of the day is of no consequence.


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## Rob3rt (11 Jun 2014)

I don't know what their algorithm is...


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## JoeyB (11 Jun 2014)

I'm confused too...why does it need to take into account the average calorie requirement for a man or woman? It just gives an estimate of what you've burnt...its not apportioned to anything?


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## fossyant (11 Jun 2014)

Back to the OP, none are accurate, they are just a guess.


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## Rob3rt (11 Jun 2014)

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


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## fossyant (11 Jun 2014)

Cut and pasted:-

Calorie calculations are only estimates. You may notice differences between Strava's calculations and those from other tools, even given the same activity data. This is most likely due to differences in Calorie calculation algorithms, and the data factored into the calculations. We believe our estimation is as accurate as possible given the limitations in data.

Guessed !!!


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## Rob3rt (11 Jun 2014)

I have got about 18 months worth of power data, the power meter calculates energy transferred to the crank in kJ (since it knows torque and rate of rotation this can be computed), if you look up the relationship between kJ and kCal and also the accepted range of human efficiencies (25% give or take a few %), you will find that these 2 conversion factors very nearly cancel out (with some individual variance accepted).

Even though they do not exactly cancel out, assuming they do still tends to lead to a better estimate than most other methods outside of a lab, i.e. I have a pretty good idea of how many calories I am burning per mile, or per hour etc.

If I calculate total energy expended over total miles, I get the value 44.22 kJ/mile, assuming the 1:1 ratio, we come to an estimate of ~44 kCal per mile. Total energy expendature over total time riding, I get the value 770.15 kJ/hour, so an estimate of 770 kCal/hour. Of course this then suggests an average speed (all time) of 17.5 mph.

Take the 1st one, 44 kCal per mile, is close to the rule of thumb Vickster commented on. Not sure where she read that? But I have posted the above before, albeit with less data.


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## vickster (11 Jun 2014)

Can't recall to be honest! Read it somewhere as 40, I err on side of caution with 30, as although I am heavy, it's flat round here and I average 13-15mph and don't get very sweaty or out of breath!

There's stuff on the web, eg http://caloriesburnedhq.com/calories-burned-biking/


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## Cold (11 Jun 2014)

vickster said:


> Can't recall to be honest! Read it somewhere as 40, I err on side of caution with 30, as although I am heavy, it's flat round here and I average 13-15mph and don't get very sweaty or out of breath!
> 
> There's stuff on the web, eg http://caloriesburnedhq.com/calories-burned-biking/




When I use that link I get closer to my MMR calories burnt and Strava is around 1500 calories out


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## vickster (11 Jun 2014)

Does it matter?


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## Cold (11 Jun 2014)

vickster said:


> Does it matter?



As the thread is about the accuracy of the calorie counter in Strava then yes it probably does.


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## vickster (11 Jun 2014)

That assumes maybe mmr used a similar algorithm. What it really means is, if correct.....

You can have two bits of cake on your next ride then . Only reason I cycle 

Personally, there is no way I burn 60+ calories a mile or I might actually lose weight eventually through cycling !


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## Mike J (11 Jun 2014)

Appreciate the responses, thank you. I won't be relying on this data anytime soon then, but at least it provides some sort of rough indication.


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## jarlrmai (13 Jun 2014)

Just forget about calories burned when cycling its not worth it, enjoy cycling get fitter and count your calories in the kitchen if the goal is to lose some weight.


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## Ganymede (13 Jun 2014)

I had my resting metabolism measured recently by my friend who is a diet counsellor. Very interesting thing to have done - you have to starve for 4 hours (not difficult if your appointment is just before lunch!) then sit quietly for 10 mins with an uncomfortable peg on your nose and a tube in your mouth that you breathe into normally. This gives the amount of calories you would use if you sat in a chair all day, which varies widely with different sizes/ages/physical types of person and from which the testing person can extrapolate your actual calorie usage. They have to rely on a questionnaire of what you say you do all week so you have to not lie about how much exercise you do.

Mine came up as about 1900 per day, taking into account my cycling and general activity. Actually quite high for a 50-year-old woman - the "2000 per day" is no good for you when you're a, ahem, mature person....


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