Change Window Border Width in Windows

This guide shows you how to adjust the thickness of window borders in Windows 10 and Windows 11. By default, borders are a few pixels wide, but you can make them thicker for easier grabbing or thinner for a more compact look. You’ll need to edit the Windows Registry, so follow the steps carefully and back up your registry first.

What You’ll Need

• A PC running Windows 10 or Windows 11 (the steps are identical for both).
• Administrator access to your user account (you’ll need it to save registry changes).
• A few minutes of time and a steady hand with the mouse.

Step-by-Step

1. Open the Registry Editor. Press Win + R to open the Run dialog. Type regedit and press Enter. If prompted by User Account Control, click Yes.
2. Back up your registry (recommended). In Registry Editor, click File > Export. Choose a location, give the file a name (e.g., registry-backup.reg), ensure All is selected under Export range, and click Save. If anything goes wrong, you can double-click this file to restore your settings.
3. Navigate to the Advanced Appearance key. In the left pane, expand the folders in this order:

   HKEY_CURRENT_USER\Control Panel\Desktop\WindowMetrics

   You can also paste that path into the address bar at the top of Registry Editor and press Enter.

4. Locate the BorderWidth value. In the right pane, look for a value named BorderWidth. If you don’t see it, right-click in the empty area, select New > String Value, and name it BorderWidth.
5. Edit the value. Double-click BorderWidth. In the Value data field, enter a number. The default is -15 (which equals 1 pixel). Lower numbers make borders thinner, higher numbers make them thicker. For example:
   • -15 = 1 pixel (default)
   • -30 = 2 pixels
   • -60 = 4 pixels
   • -120 = 8 pixels

   The rule is: the more negative the number, the thinner the border. So -10 is thicker than -15. Click OK.

6. Restart Windows. The change doesn’t apply until you sign out and back in, or restart your PC. Click the Start button, select Power, and choose Restart. (You can also sign out and sign back in, which is faster.)
7. Check the result. After restart, open any window and look at its edges. If the border is too thick or too thin, repeat steps 3–6 with a different number.

Common Mistakes

• Using a positive number. Positive numbers like 15 are ignored by Windows; the border width stays at the default. Always use a negative value.
• Typing decimals. The value must be a whole number (integer). Entering -15.5 may be rejected or cause unexpected behavior.
• Editing the wrong key. Make sure you’re in HKEY_CURRENT_USER\Control Panel\Desktop\WindowMetrics, not HKEY_LOCAL_MACHINE or another location. The path is case-sensitive in the sense that it must match exactly.
• Not restarting. The change won’t appear until you sign out or restart. Some users think it’s broken because they only closed and reopened the window.
• Forgetting to back up. If you skip the backup and later make a mistake, you might have to manually restore the default value (-15).

Tips

• Start with a small change. Try -30 (2 pixels) first. That’s usually enough to make borders easier to grab without looking chunky.
• Combine with PaddedBorderWidth. In the same registry key, you’ll also see PaddedBorderWidth. This affects the invisible padding around the border that helps with touch and pen input. If you want a truly minimal look, you can set it to 0, but that may make resizing with a mouse harder.
• Use the sign-out trick. Instead of a full restart, click your profile picture in the Start menu and choose Sign out. Then sign back in. This is often faster.
• Reset anytime. To go back to the default, simply set BorderWidth back to -15 and restart.
• Note for Windows 11. In Windows 11, the border width also affects the rounded corners’ visual thickness. Very thick borders (like -120) can look odd with rounded corners, so test with a moderate value.

Troubleshooting

• Nothing changed after restart. Double-check the registry path. It must be HKEY_CURRENT_USER\Control Panel\Desktop\WindowMetrics. If you accidentally created a new key instead of a string value, delete it and create a String Value named BorderWidth.
• Borders are uneven or look broken. This can happen if you set an extremely high value (like -500). Reset to -15 and try a smaller change.
• Registry Editor says “Cannot edit BorderWidth: Error writing the value’s new contents.” This usually means you don’t have write permission to that key. Make sure you’re logged in as an administrator. If you are, right-click the WindowMetrics key, choose Permissions, and ensure your account has Full Control.
• The value resets to default after a reboot. Some third-party customization tools or group policies may override the registry. Try disabling any such software temporarily. Also, make sure you’re editing the correct BorderWidth under HKEY_CURRENT_USER, not HKEY_LOCAL_MACHINE (the latter may be overwritten).
• You can’t find the BorderWidth value. It’s not present by default in some Windows versions. Just create it as described in Step 4. Right-click in the right pane, choose New > String Value, and name it exactly BorderWidth.

Frequently Asked Questions

Does changing BorderWidth affect all windows?

Yes, it affects the standard window borders for most applications, including File Explorer and many desktop programs. Some apps (like modern UWP apps) may not respect it, but the classic desktop windows will.

Can I make the border width zero?

Technically you can set it to 0, but Windows may ignore it or render a very thin border. In practice, a value like -1 gives the thinnest visible border.

Is this safe? Can it break my system?

Editing BorderWidth is safe if you stick to reasonable values (between -1 and -300). It only changes the visual appearance. However, always back up the registry before making changes, and never edit other values unless you know what they do.

Why does the border width revert to default after a Windows update?

Windows updates may reset certain visual settings to default. You can simply reapply the registry change after an update. If it happens frequently, consider using a third-party tool, but those come with their own risks.

Can I change the border color as well?

Yes, border color is controlled by the system accent color or the classic color settings. In Windows 10/11, go to Settings > Personalization > Colors to change the accent color. For more control, you can use the legacy Window Color settings, but that’s beyond the scope of this guide.

Does this work on Windows 7 or 8?

The registry path is the same, but the visual behavior may differ. Windows 7 and 8 also use BorderWidth, but the default value may be different. It’s still safe to try, but you may need to experiment with values.

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