How do I know which one is right?

Alright. First of all, I have myself listed as "light activity" because I try to go on 1.5-2 mile walks daily. I also have to take a lot of stairs to get to my classes every day and I live on the 11th floor of my dorm and try to take the stairs up once or twice a day. So I don't really know if that's "light" activity or not to begin with.

Then there's the discrepancy between CC's burnmeter, which says I burn about 2250 a day, Nutritiondata.com, which says it's about 2400, and some other site I've forgotten which says 2550.

Now I'm 18, 5'6", and around 180-185 last I checked. Which one of those 3 sounds right to you? And also, should I set my meter to sedentary? Or is light appropriate?

I think that since you are just starting off, you might want to start at sedentary and add in your activity calories until you really know how many activity calories you are burning. And also, I would trust the CC numbers. That seems like a big difference between this and other sites, and I think CC is pretty close.

Oh, I'm not really new. I just forgot my old username/password over the summer. The problem with just logging my activity is that I can't really log the individual trips up the stairs because I don't know how long it takes me to get up each flight and my speed varies, etc.

I guess I will just trust the CC numbers, though. Anyone else think I should change my activity level to sedentary?

CC's number sounds *really* low to me.  Are you sure that's not the suggested amount you eat?  I weigh 25ish pounds less than you, am two inches shorter and am 14 years older.  All of which should make my daily burn less than yours - and, at lightly active, I burn about 2050 cals/day.