How much gb does my iPhone 4 have?

Capacity: 13.7 Available: 13.0

Version: 6.0.1

Want to know if its 4gb 16gb or 32gb and how do i find out? Does it need calculation?

Its a 16 gb

It's a 16gb, they take off a bit for all the software and stuff, so there's less. (this is what I think anyway)

Settings/general/usage

16gb

Well obviously it would not be a 4GB since the capacity is 13.7GB. Nor will it be 32GB.

Its 16GB. You don't get all 16GB as some of it is used to store iOS & other files.

I don't think there ever was an iPhone with just 4GB.

"how do i find out?"

You could look at iTunes.

You could also look for a site that will identify Apple products by their serial number.

You can also look at the back of the iPhone. Apple typically stamps the capacity on the back of the device.