How to understand what is taking up space in Iphone and clear it?

Question

iOS

I ran into it once again and far from on the same device - you look in the settings - in the storage management where the place is occupied by something ... you summarize (you were not too lazy to write out the numbers in Excel) and it turns out that somewhere "disappeared" well, let's say 7GB.
and what is busy at all is not clear. and on the 32GB model it is noticeable. not to mention 16GB models ...
we make a backup (I chose a backup on the computer via itunes) - a copy was made, but for some reason the applications were not restored, I installed everything again, since the settings were picked up by everything and chats-correspondences.
in general, such a "maneuver" returns it is not clear where the departed place is, but it is inconvenient and not for long.
all sorts of programs like phoneclean did not find anything interesting ...

Answer 1

Firstly, Apple considers its place based on the figure 1 megabyte = 1000 kilobytes, and not 1024 as we used to consider it. There are a lot of discussions about this on the Internet. Even lawsuits.
Secondly, all the memory is clogged with the application cache. Browser, Instagram, received files in Telegram, logs (if the application writes them).
You just couldn't lose 7 gigabytes.
phoneclean only scans the places where you have ticked.