iPad mini GB usage issue

It's probably cached data. Try backing up your iPad to iTunes then delete stuff so you can do the update. Then do a restore with iTunes.

 

The OS takes up some of the space automatically. You never receive the full advertised amount of GB for any electronic device that you buy.

 

Nothing new, but yes, 16GB iPad/iPhone is almost useless, 32GB should be minimum storage, Apple has been milking this for years

 

Out of the box a 16GB unit is really only 15.625GB. Then you have to subtract the size of the OS and all preinstalled software.

A storage device with 16GB is 16,000,000,000 bytes. But in reality, 16GB is actually 17,179,869,184 bytes which translates to the .375GB that is lost. Then the OS is 1.5GB-2GB, which accounts roughly for the 2.5GB that you are missing.

 

Don't just delete stuff. Take a look at your usage and address what's eating your space. Clearing small stuff is not going to fix your problem.

 

I can't believe Apple sells a iPad that has less than 32 GB. Well, yes I can too.

 

If you stream music on iTunes Match or stream video from iTunes I think some memory is used as a cache. I've noticed that after a reboot I sometimes "reclaim" some memory because the cache is deleted.