Based on other calculators and experience with losing/not losing weight, I estimate that fitday's calculations for calories burned, both for sitting around and most exercise activities, is about 50% more than (i.e. 1 1/2 times) what I actually burn. So if I subtract about 1/3 from whatever they say my daily calorie burn is, the math adds up better for what I'm seeing on the scale. I don't think I have an abnormally slow metabolism, their figures just seem high, like you said. So maybe try 1800 as your starting point and see how that works.
