Where is the memory hog

[pithlet]

I have a S4 with Lollipop 5.0.1. It has 16GB or really 9.72. Ever since updating I have been constantly fighting for space on my phone. There is only a certain amount I have been able to move to my external sd card. Now it again is hovering around 300-400 megabytes. When I look at the top level folder, 0, all the folders only take up 724MB. So where has the rest of my memory gone? I have cleared the cache and that was not the issue. I have looked around and have yet to find a definite answer or solution.

Sidenote: I was using ES file explorer to look around and once when I was using its SD Card Analyst I some how got it to go above the normal top folder, something I have not been able to repeat. When it was analyzing it quickly went above the 9.72 GB but I was only surprised when it continued finding files up to over 30GB... I am unsure as to what was going on. At some point it froze... Any idea what happened?

 

[B. Diddy]

Welcome to Android Central! Unless the phone is rooted, you won't be able to access directories of system apps or preinstalled bloat apps. So the directories that you can look at in a file manager app won't give you the whole story.

Go to the App Manager, make sure it's set to show all apps (including Hidden and System apps), and see if you can sort them by size. Does anything stand out there?

 

[Rukbat]

Remember, about 8 of that 16GB is for Android, so there's only 8GB left for you.

The apps themselves are in root space, so you can't see the files, but they still take up space. So does the data those apps are storing (like your current score in the game).

A 16GB phone isn't a very large phone today, which is why the S7 comes in 32 or 64GB models (and 64GB is squeezing things for some people). How large is the hard drive (which serves the same purpose) on your desktop or laptop? Not just 64GB?