Windows 11 monitor scaling not independant

[MatsW]

I have an extra monitor (3840x2160) 42" attached to my laptop (2560x1600) 16". I'd like to have the same size of objects on the two screens, so I set Scale to 150% on the laptop screen and logout. But when I login the extra monitor Scale has been changed to 150% which makes everything on that screen too large. So I set Scale on extra monitor to 100% and logout. But when I login Scale on laptop screen has been changed to 100% which makes objects too small.
What is the procedure to set different scaling between the different screens?

 

[ChatGPT]

Fix: Keep different scale per monitor in Windows 11​

Your sign‑out behavior suggests “Custom scaling” is enabled, which forces one scale for all displays. Turn that off, then set scale per monitor.

• Turn off global custom scaling:
  • Settings > System > Display > Scale > Advanced scaling settings
  • If a number is set under “Custom scaling,” click “Turn off custom scaling and sign out.”
• Set per‑monitor scale (no need to sign out between changes):
  • Settings > System > Display
  • Select the 42" 3840×2160 display > Scale: 100% (Recommended)
  • Select the 16" 2560×1600 laptop display > Scale: 175% (this best matches physical size with the 4K screen at 100%; 150% is fine if you prefer smaller)
• Verify both are at native resolution:
  • Settings > System > Display > Advanced display > check each monitor’s resolution.

If it still resets, tell me your Windows version (Win+R → winver) and whether “Custom scaling” keeps reappearing.

 

[MatsW]

There is no Settings > System > Display > Scale > Advanced scaling settings
And there is no "Turn off custom scaling and sign out" in any of the alternatives

 

[ChatGPT]

Why this is happening​

Windows is applying “Custom scaling,” which forces one scale to all displays at sign‑in. That’s why whichever screen you change last becomes the scale for both after you log in again.

Turn off global Custom scaling (newer Windows 11 UI)​

If you don’t see “Advanced scaling settings,” Microsoft likely moved/renamed it in your build. Do one of these:

• Settings search (easiest):
  • Win+I → in the Settings search box, type: custom scaling → open the result named “Custom scaling.”
  • If a number is set (e.g., 150), choose Turn off custom scaling and sign out. If there’s no button, clear the value so it’s blank, then sign out.
• Registry (direct reset):
  • Win+R → regedit
  • Go to: HKEY_CURRENT_USER\Control Panel\Desktop
  • Set Win8DpiScaling to 0.
  • If LogPixels exists, delete it.
  • Sign out and back in.
  • Note: editing the registry changes system behavior immediately—only proceed if you’re comfortable.

Then set different scale per monitor​

• Win+I → System → Display.
• Click the 42" 3840×2160 display → Scale: 100% (Recommended).
• Click the 16" 2560×1600 laptop display → Scale: 175% (this closely matches physical size to the 4K screen at 100%; use 150% if you prefer smaller).
• Make sure both are at native resolution (Advanced display → check each monitor).
• Important: Set both scales, then sign out once (only if prompted). Don’t sign out between each change.

If you still can’t find the Custom scaling page, tell me your exact Windows version (Win+R → winver) and I’ll give steps tailored to that build. A screenshot of Settings → System → Display → Scale & layout would also help.

 

[MatsW]

Search for "Custom scaling" didn't work, but regedit metod worked.
Windows 11 version 24H2

 

[ChatGPT]

Great—thanks for confirming. On Windows 11 24H2 the “Custom scaling” UI is easy to miss and sometimes doesn’t show if a value is enforced. Your registry reset (Win8DpiScaling=0 and removing LogPixels) re‑enabled true per‑monitor scaling, which is why it’s now behaving.
Do this to finish up and keep sizes matched:

• Set per‑monitor scale (don’t sign out between changes):
• Settings > System > Display.
• Click the 42" 3840×2160 display → Scale: 100% (Recommended).
• Click the 16" 2560×1600 laptop display → Scale: 175% (this best matches the physical size of the 4K screen at 100%; try 150% if you prefer smaller).
• Make sure each display is at its native resolution (Display > Advanced display).
• If any apps look blurry when moved between screens, enable “Fix scaling for apps” under Display > Scale (name can vary slightly in 24H2).

If it ever reverts again, recheck the same registry keys, or use this PowerShell one‑liner to reset and sign out:
reg add "HKCU\Control Panel\Desktop" /v Win8DpiScaling /t REG_DWORD /d 0 /f & reg delete "HKCU\Control Panel\Desktop" /v LogPixels /f & shutdown /l
Need help dialing in exact parity between the two screens? I can suggest a scale based on your exact viewing distance, but 100% (4K 42") + 175% (16" 2560×1600) is the closest match for most setups.