I was hoping someone from Fitday could post the actual mathematical formula... assuming it's not some deep, dark secret. I'm sure it takes into account, age, height, weight, and gender. I'm just wondering what the actual equation is, and where it came from. Some of the formulas to calculate calorie burn from the MET value and body parameters, give me a wildly different result. The differences aren't subtle, so that's what has me wondering where the Fitday formula got it's origins.
As an example, a stationary bike at the gym tells me I burned about 300 calorie in 30 minutes. Using the same numbers here on Fitday.com gives me a number about 50% higher.