How many gbs does my iPhone 4 have?

I went to General -> About -> Capacity and it says that I have 28.5 gbs and that 22.8 is available but the only options are 8, 16, and 32.

It should say it on the back of the phone or box or you can check in your (phone) storage

You have a 32 gb because it takes about 4 gbs for all the apps that come pre-installed as well as the software. I also have an Ipod with the excact same thing and I bought 32gb.

You have a 32 GB iPhone.

Not all of the memory is available for music/apps/etc…