How much space does Ubuntu take up after it's already installed?
I know how much space is required to install Ubuntu.
How much space does a Ubuntu installation take up on the disk?
Solution 1:
According to installation procedure 4.5 GB approximately for Desktop Edition . It varies for Server edition and net-install .
Please refer this System Requirements for more info.
Note : On a fresh install of Ubuntu 12.04 - 64 bits without any Graphic or Wifi drivers took approximately 3~ GB of File system space. And i guess 4.5 GB is recommended for Updating packages , Language packs , etc and best practical reason is for Ease and Smooth Usage of System avoiding Low memory kind of situations.
Solution 2:
Update (September 2019)
A Minimal installation of Ubuntu 19.04 Desktop (64-bit) uses 3405M on / plus 86M on /boot according to df -BM. This is after I disabled and deleted the 2033M file /swapfile. Additionally, apt-get autoremove can lower disk usage on / to 3331M.
Update (April 2018)
A Minimal installation of Ubuntu 18.04 Desktop (64-bit) uses 4195M on / plus 76M on /boot according to df -BM. It is possible that more space is required during the installation itself, as a Minimal installation may start with a Normal installation and then remove a predefined set of packages.
Unfortunately, after (1) performing a Minimal installation, (2) rebooting and (3) logging in via the graphical login screen, all I get is (4) a mouse cursor. No menus, no icons, no ability to run any programs, and no ability to log out.
A Normal installation of Ubuntu 18.04 Desktop (64-bit) uses 4732M on / plus 76M on /boot according to df -BM.
Unfortunately, even with a Normal installation, I still do not get a working graphical desktop. My laptop is an Acer Aspire One with 2GB of RAM. The live ISO of 18.04 runs acceptably.
Additional update: If you have no swap partition, Ubuntu 18.04 seems to create a swap file at /swapfile. In my case, the files was about 1GB, but I don't know how much of it was actually used. It is possibly that the unused portion of the swap file would not be included in df. After I turned off swap, removed it from /etc/fstab, and deleted the swapfile, disk usage dropped to around 4000MB on the Standard installation.
The GNOME desktop did finally appear. It took about 10 minutes, maybe more. So I'm going to try installing Ubuntu-MATE instead. I'm not attached to any particular default desktop. I generally run the Openbox window manager without any desktop environment.
Ubuntu-MATE 18.04
With /swapfile: 5679M on /, 76M on /boot
Without /swapfile: 4732M on /, 76M on /boot.
Original Answer (December 2016)
I just installed Ubuntu 16.04.1 Desktop (64-bit) on to an 8GB USB stick.
Upon booting immediately after the install, df -BM / says I have used 3418M (or under 3.5GB) of disk space.
It is possible that more space than that was temporarily used during the installation process. The system has no swap. I was not connected to a network during the install.
Annoyingly, the Ubuntu installer said that 8.5GB of space was required, and refused to install on my 8GB USB stick. I bypassed this requirement by temporarily inserting a 32GB USB stick.
Of course, depending upon what additional software you want to install, and what type of work you want to do on the system, you could need significantly more than the 3.5GB that is used, or even significantly more than the 8.5GB that the installer claims is "required".
I typically install Ubuntu onto 20GB root partitions, and store all my work data on separate partitions and disks.
Solution 3:
I create separate partition usually 20-30GB for system(at least 10GB!). Later I create /home/xxx partition for left free disk space and I use it as my home directory. Under partitioning and installation I mount my partition as home folder. This allow you very easily to re-install whole Ubuntu without loosing your data & settings.