i am 5"5 and 120.8 pounds what is my size?

i want to know my size..i a thinking 4 maybe.

like, for clothing? that would depend on a lot of things (build, style, store, etc.) The way I figure mine is to take chest, waist, and hip measurements and then go to the website of the store I'm looking to buy from. Usually, they have easy to use size charts for their online shoppers that will tell you what you would wear from their store based on those measurements.

I'm 5'5.5"  (I always say 5'6 because it's easier) and I weight 125 and I am pretty consistently a 4. In some brands a 4 is a bit loose, and in some a bit snug.  So I would say you would probably be comfortable in a 2 or a 4 in most brands. 

I'm around 5'6' and when I was 120, I wore pants ranging from a size 1 to 5. Like hapagirl said, it depends on the store and how you're built. I personally don't trust online size charts because they never seem to work accurately for me, but maybe I'm just weird like that.

Online size charts don't work for me either.  You can go into a store that you like to purchase from (or two) and just go into their fitting rooms with a couple different sizes and then say that you didn't want any of them and leave. :P  I've done it before.

You posted this in weight loss - I hope you're not planning to lose weight, because you're already at the very low end of the health weight range for your height.

It's impossible to know your size just from height and weight.  If two people weigh the same but one is more muscular, the more muscular one will be smaller.  If two people weigh the same but one is an apple and one is a pear, the pear will likely wear smaller tops and larger pants while the apple will likely wear larger tops and smaller pants.

Also, appletwo is absolutely right.  At your height/weight, you cannot possibly need to lose weight.