Calculating calories burnt during exercise

[vin01]

I have a heart rate monitor which I have been using during cardio...
At my gym, the cardio machines will tell me the amount of cals burnt during my time exercising....

However, I have decided to start doing cardio outside (running, walking, sprints, biking), and I would like to use the 4 criteria below to determine an approximate number of calories expended:

1) total time exercising
2) average heart rate
3) age
4) bodyweight

I know this isn't the optimal way to do it, but for me, right now, this is how I want to gauge my cardio workouts.

My question is: Is there any website, or formula, where I can plug those values in to get an approximate number for calories used??

K to any help! Thanks.

 

[Cynical Simian]

Obviously, calculators, like the readouts on the machines, shouldn't be treated as absolutely accurate, but they at least give you a good general idea of caloric needs. www.fitday.com has a pretty comprehensive activities database.

Example: Caulking, except log cabin - 240 calories/hr.

 

[vin01]

Haha, thanks. I'm actually planning to spend part of my weekend caulking. (go figure)

I'm gonna see how Fitday works for me.

Anybody else got any other calculators or formulas?

 

[Lifterforlife]

This is much more than a formula site, but a great one nonetheless. www.caloriesperhour.com

 

[vin01]

Thanks Lifter for the link. Great site. I gotta spread my karma before I hit you with some.