Photo by kevnkovl.

Since I started using Capital Bikeshare in late April, I’ve logged 39 trips totaling 59 miles and lasting a combined seven hours of riding. And now, thanks to a new feature made available today to all users of the District’s popular bikesharing program, I can even tell how many calories I burned and what my carbon offset was, both cumulatively and for individual rides.

It’s all pretty simple, really, since Capital Bikeshare already tracks distance and time of rides:

For carbon offset calculations, we use the goDCgo’s Carbon Calculator to determine your CO2 output, using 7.456mph as an average cycling speed. Next, we determine the CO2 output of a midsized car traveling at 21mph for the same distance as your trip. Subtracting your output from the car’s gives us your carbon offset.

For calories burned, we start with base equation of averages where a 180lb person traveling at 7.456mph burns 43 calories per mile. Your calories burned are equal to 43 calories multiplied by your miles traveled.

If you’re not the standard 180 pounds that Bikeshare uses as a reference point, though, fear not — they’ve even got an Advanced Calorie Calculator that allows you to enter the duration of your ride and your weight.

All told, I’ve burned 2,352 calories and spared 37.14 pounds of carbon dioxide from entering the atmosphere since April. And though the District Department of Transportation doesn’t keep cumulative stats for the calories burned by all of the 17,007 annual members and 1,270 monthly users, the system was able to offer up this much data — between September 2010 and July, Capital Bikeshare users have pedaled 889,534 miles. Using the calculations they offer up on the Bikeshare website, that’s roughly 382,499,362 calories burned lugging the system’s 40-pound bikes around in just under a year — or about the amount contained in 6.4 million bakery cupcakes, around 355 per Bikeshare user.

Capital Bikeshare turns a year old on September 20, and a party (with cupcakes, we hope) is scheduled for September 22 at The Yards Park. They’ve even promised multiple moon bounces.