Please tell me if this calculator is correct

pamwhite712

http://www.braydenwm.com/calburn.htm

I have a HRM, but can't understand the readout for the calories burned. It seemed impossibly high. So I entered in the data on this site (gender, age, weight, average heart rate, duration) and it gave me a number for calories burned.

Now I know I'm way out of shape, but this is even higher than what MFP gives me!