MY iPhone 6 16 GN only has about 11 gb of
storage total a real rip off always running out
of storage never did on my iPhone 5 when years
up turning it in.
the operating system take up the rest of the storage
likely your older iPhone took photos which were not as many megapixel so did not take up as much room
It's a little bit more complicated than just the OS taking up space. See this article for a full explanation:
How OS X and iOS report storage capacity - Apple Support
What you're seeing is true of pretty much every computer hard drive/floppy disk/USB drive/SSD every created.
The available storage on a 16 GB iPhone 6 is about the same as the available storage on your 16 GB iPhone 5c. If you are fitting less on it you are using functions that require more storage than the functions you were using on the 5c.
I have less storage with I phone 16gb than with my 5c only about 11 gb
