If you connect a modern 4K or 5K high-resolution monitor to an Ubuntu Linux machine, you will immediately encounter a scaling issue. By default, the GNOME desktop environment only supports integer scaling (100%, 200%, 300%). At 100%, text and interface elements on a 4K screen are microscopic and unreadable. If you jump to 200%, everything becomes comically massive, wasting all your expensive screen real estate.
What you actually need is something in between, like 125% or 150%. This is known as “Fractional Scaling.” While this feature has been standard in Windows and macOS for years, it is still considered experimental in Ubuntu’s default X11 display server due to historical rendering complexities, and is therefore hidden from the standard settings menu.
How to Enable Fractional Scaling in Ubuntu (X11)
You must use a terminal command to unlock the fractional scaling options in the GNOME control center.
- Open your Terminal application (Ctrl + Alt + T).
- Carefully copy and paste the following exact command:
gsettings set org.gnome.mutter experimental-features "['x11-randr-fractional-scaling']" - Press Enter to execute the command. (Note: It will not output any confirmation message; it simply returns to the prompt).
- Click the network/battery icon cluster in the top-right corner of your screen and select Settings.
- In the left-hand navigation sidebar, scroll down and click on Displays.
- You should now see a new toggle switch labelled Fractional Scaling. Click it to turn it On.
- A new row of scaling percentages (125%, 150%, 175%) will instantly appear.
Select 150% (or whichever value looks best on your specific monitor) and click the green “Apply” button at the top right. Your screen will briefly go black and then redraw the entire desktop environment at the perfect size, balancing legibility with screen real estate. Warning: Fractional scaling on X11 can slightly increase CPU usage and cause minor screen tearing in some full-screen games.