How to tell how many gigs my iPhone 4 is?

It says 6. Something is that possible? It says that in capacity

I've only had an Ipod touch but it was an 8 gig that came with about 2 gigs of data already filled.

If you did settings>general>about then 6gb is all you have bcuz mine say 28.6gb since i have the 32gb. You might hav the 8gb model. Not sure if i'm right bcuz i only hav the 4 not the 4s

Yeah, it says it is supposed to be 8, but a lot of that space is used up for the operating system, showing less.

It says so on the back. If it says 6 in the options thingie then you have used up some of that space or it's an 8 GB with some of the space used up from the get go by the iPhone itself.