If your BMR is too low, try changing your goal or your start/stop dates. If you're trying to lose too much in too short a time, the calorie count won't look right. The 1618 is more like it for someone your size, then to lose weight you would either subtract some calories or exercise more.
Well, I thought it was kinda low. only ~883, I'm 5'7", 24 y/o and 175 lbs. I used a BMR calculator online and it was 1618. I'll see if it changes as I enter more data, if not I'll email support, because I really think the number it shows is really low.
It should calculate it on it's own. If not I would email support about it.
It should calculate using the information you enter.