For my fit bit using friends, a question....

 Do you find it accurate on the counts? Tonight I went out for a quick walk, I know from Map My Run (and doing a drive though with my car) that the outside circle of my neighborhood is 2 miles almost exactly, went around twice tonight wearing the FitBit and it said I did 3 miles, and that I was walking much faster then I think I was. 

Any input? Does it have to be adjusted for stride length? Is there a way to do that? 

I have found it very accurate. there is a way to adjust stride on the web site.. I can't remember how right now , but I am sure you will find it there.
Julie