I am sure it varies depending on the stats you put in to FitDay. For example, at my age and size, it tells me I burned 1831 today, but I'm only 5'2". However, like Lizzy, I log in sleep and it gets me to the right balance of numbers.
You could try to find some other sites that estimate your calorie burn by Googling "how many calories do I burn a day" and plug in your info to see if it's a similar result. Here's one I like to use: Calorie Calculator - Daily Caloric Needs