calorie formula?

[jmechy]

I'm sure this has been posted before, but I can't seem to find it among the millions of calorie threads.
Is there a formula that I can plug my height and weight into, along with the speed/distance/time/cadence/heart rate of a ride to get calories burned or even watts? I have a pretty decent excel chart going of all my rides that contains all the above data, and would like to throw in something that would allow me to compare how hard I actually worked on any given ride and compare it to previous rides. Even if the figure isn't totally accurate, as long as it is reliable it will help.

[jennip]

bicycling.com has a pretty decent one. Look under the training tab. It doesn't let you plug in heart rate, but it does ask for weight, length of ride, and average speed. Hope this helps! I also have excel spreadsheets!

[NomadVW]

Not without making a lot of assumptions. Power estimations (and therefore calorie estimations) will require a lot of "estimated" factors like grade, wind, and aero drag. Best way to do it would be to create a personal "RPE scale" in your spreadsheet to record your own perceived exertion. For many, it can be just as accurate.

[SSP]

The rule of thumb is 40 calories per mile. A little more if you're larger, or climbing a lot of hills. A little less if you're smaller, riding mostly on the flats, or drafting in a pack.

FWIW, if you like keep track of that sort of thing, my CycliStats (http://www.cyclistats.com) program includes a calorie calculator that automatically estimates calories burned and average wattage for each ride.

[grebletie]

The rule of thumb is 40 calories per mile. A little more if you're larger, or climbing a lot of hills. A little less if you're smaller, riding mostly on the flats, or drafting in a pack.

FWIW, if you like keep track of that sort of thing, my CycliStats (http://www.cyclistats.com) program includes a calorie calculator that automatically estimates calories burned and average wattage for each ride.
40 calories per mile will get you a pretty accurate estimate. Comparing what my powermeter reports for Kj burned (fairly close to kcals burned), the number is right around 40 calories per mile.

[jmechy]

Not without making a lot of assumptions. Power estimations (and therefore calorie estimations) will require a lot of "estimated" factors like grade, wind, and aero drag. Best way to do it would be to create a personal "RPE scale" in your spreadsheet to record your own perceived exertion. For many, it can be just as accurate.

I always start and stop in the same place, so couldn't I assume 0 wind and 0 grade?

[brianallan]

To me it seems as though heart rate would be the best indication of calories burned, not power. A rider in the tour de france leisurely riding at 24 mph with a heart rate of 140bpm is certainly burning less calories than me riding at 24 mph (160bpm?). Am I completely off on this?

[dahoss2002]

To me it seems as though heart rate would be the best indication of calories burned, not power. A rider in the tour de france leisurely riding at 24 mph with a heart rate of 140bpm is certainly burning less calories than me riding at 24 mph (160bpm?). Am I completely off on this?

So very true..... And a 200 lb. obese person would burn more CPH than a 200 lb athlete, both riding at 15 mph. Riding a 40 lb. walmart Mt Bike uphill prolly burns more CPH than riding a 20 lb. roadbike up the same hill for any size person. Ive see some ridiculously high calorie burned estimates that try to figure in weight and wind speed and other variables. I guess one day some one will find a good program using all the variables including heart rate, but I like the simplicity of 40 calories per mile. 25 mile ride = 1000 cal. + or - depending on lots of things but a very workable estimate.

[NomadVW]

I guess one day some one will find a good program using all the variables including heart rate

As heart rate has no bearing on work being done (but rather is a physiological response to the work), someone already has. They're called power meters. You won't get much more accurate than that.