This BMR Calculator tells you the amount of calories you'd burn if you just stayed in bed all day. So it's kinda like @Raining_again's minus the exercise.
Last night I went out running with a guy that I thought was going to be rubbish. He was amazing and didn't even know it. We basically started out at a sprint (for me), and then at the end of 3.1 miles (tracked it on my phone) he said "Oh I thought that was just about 2 miles, I've done that in 17 minutes before." I was so annoyed.