How to check and calculate which folders size?

On the files tab I have information, that I already used 944 MB out of 1 GB. I want to clean my folders from trash, but can't understand which uses so much space. I run du -hs /home/ and it gave me only 112M. So where is all the other data, which takes all my space?

also check /tmp etc?

May I freely delete everything in /tmp and /var? Btw, found nethack in /var folder, love this game ))

yes for /tmp- although keep in mind that some of your own scripts might be using /tmp etc. for /var, I think only select folders under /var are user writeable.