How many gigabytes does my Iphone 4s have?

I want to sell my iPhone 4s but, I have no idea how many gb it is. I'm really confused. The number is not on the back of the phone like how my Ipod is. I went to settings- general -about and the capacity is 13.2 GB and available is 12.8 GB. The only options on Ebay are 16 GB, 32 GB, and 64 GB… Not 12 GB… How many GB does my iPhone have?

You have a 16gb iPhone, it shows up as 13.2 because the software takes up some memory.

It's a 16GB iPhone 4S and the available space is 12.8GB

That's a 16GB model. You don't get all 16GB to use so 13.2GB is what you get after iOS & its files. Roughly the same lower numbers for the 32 & 64GB models.

Oh & not only Apple does this nor is this limited to smartphones. Standard procedure.

It's probably a 16 gb because the OS takes up some room & the apps eat up some too. There should be a place on your phone (probably under settings) that tells you exactly how much storage you have!