Make text and interface elements a similar size across different displays

Make text and windows a similar physical size when you move between a laptop and a larger monitor. UI scale matching follows one display's desktop size and chooses suitable existing modes for the others, so their resolutions can differ while their interface sizes come closer.

Before you begin

Choose two connected displays with different physical sizes or pixel densities, such as a smaller built-in display and a larger external monitor. Use separate extended desktops for the first test: a mirrored target is skipped. Pick the display whose text size you find comfortable as the watched display. The affected displays will follow it.

Check that each affected display offers useful display modes at the refresh rate you want to use. If the choices are too sparse, complete Set up a fully scalable HiDPI desktop first. Flexible scaling adds choices on supported displays. Scale matching chooses from existing modes.

Note each display’s current resolution, HiDPI state, refresh rate and bit depth so you can return to that mode. If Configuration Protection is enabled, note its saved resolution and refresh-rate targets too. They may differ from the current mode. Save your work before changing modes because the picture can briefly disappear.

Check the physical size used for matching

Matching uses the width and height of the visible image area, excluding the bezel. Check the reported values against the display’s specifications or measure that area. If the app uses an estimated fallback, correct it before matching.

  1. Open Settings > Displays > [display] > General Settings > Additional Settings….
  2. Check Display physical dimensions. Note whether each field is empty or has a saved value. An empty field may still show a calculated or reported value as a hint.
  3. If the values are wrong, enter positive, verified width and height in millimeters for the panel's normal unrotated orientation. Repeat for the other display. Do not substitute the desktop's pixel dimensions or guess from a product's rounded diagonal size.
  4. Select Done. The dimensions save as app settings. No system-configuration Apply or restart is needed.

XDR Additional Settings with hardware-reported physical dimensions 599.3 by 329.5 millimeters and resolution-range limit off

The XDR reports 599.3 × 329.5 mm. These are the entered values, rather than an independent measurement of the screen.

Choose one display to follow

Use a dedicated display group for this first test. Prepare its membership and matching rules while it is disabled, then activate it when the choices are complete. Group membership chooses the displays available to the rule. The watched list chooses who starts matching, and the affected list chooses who receives it.

Before testing, record and temporarily pause any other UI scale matching rules involving these displays. Otherwise a source change can affect additional targets through another active group. Restore those original rules after the comparison.

  1. Open Settings > Groups > Overview > Create New Display Group…, name it UI Size, and select Create Display Group. Turn Enabled off while you configure it. A new group starts enabled and exclusive, so creating it may briefly pause lower-priority groups. Check that any existing desk groups are active again after disabling the new group.
  2. Under Group Membership, turn Treat all currently connected displays as group members off. In Member displays, select only the watched display and the displays you want to match.
  3. Open Configure Activation Rules… and select All configured group member displays are connected. If other connected displays should be allowed to remain outside this group, turn Only group members can be present off. You do not need to enable synchronization or layout protection for this task. Select Done.
  4. Under UI Scale Matching, turn Enable UI scale matching on. Leave Update resolution configuration protections off for the first test, so displays with protected resolutions stay unchanged.
  5. Open Advanced UI Scale Matching Settings…. Turn Watch all group members for resolution changes off, then select exactly one display under Watched group member displays.
  6. Turn Match UI scale of all group members off. In Affected displays, select only the displays that should follow the watched display. Leave the watched display and other members off.
  7. Leave Matching tolerance empty for the default 10%, and keep Watch for resolution changes made outside of the app off. Select Done to close the sheet.
  8. Turn the group's Enabled switch on and check Activation for Display group is currently active. If it remains inactive, resolve the displayed reason before testing.

Advanced UI scale sheet with FlipAction Pro watched, XDR affected, outside watching off and native default tolerance

FlipAction Pro supplies the size to follow. Only the XDR is selected to change to matching modes.

The two automatic member lists start on in a new configuration. Selecting the members yourself limits matching to the intended source and receivers. Changes save as you edit. No Apply or restart is needed.

Change the watched display and try a manual match

  1. Open App Menu > [watched display] > Display Mode. Choose a different known-working logical resolution that gives you a comfortable interface size. Use the resolution slider instead if you prefer.
  2. Wait for the change to settle, then inspect the affected displays. BetterDisplay looks for a nearby mode that brings their physical interface size toward the watched display's size while looking for a mode that keeps each target’s current aspect ratio.
  3. To try manual matching, use an affected display's Display Mode menu to choose a different known-working desktop size. This display is not watched, so it does not drive this group's match.
  4. Open App Menu > [watched display] > Manage Display > Match Group UI Scales. This uses the watched display's current mode without changing that source. Recheck the affected display for a suitable match.

FlipAction Pro attached App Menu with Manage Display expanded and Match Group UI Scales enabled

Run matching from the watched FlipAction Pro display without changing its current desktop size.

The manual action still needs an active group with matching enabled and that display accepted as a watched member. It works with outside-change watching off. It does not align every connected display regardless of the group's lists.

Check the result

Move the same document window between the displays without changing its font size or app zoom. Compare the physical size of text and familiar interface elements on the actual screens. Similar text and interface size is the goal. The panels may still have different pixel densities and sharpness.

Check each target's current Display Mode and Refresh Rate selections after the match. Matching looks for a mode with the target’s current refresh rate, bit depth and HiDPI state. A native-mode exception can change HiDPI, so check that too. The source's refresh rate is not copied to the targets.

A target stays unchanged when no suitable available mode is close enough. Both target dimensions must be within tolerance. A wider tolerance allows a less exact size match. Keep the default for the first comparison rather than raising it to conceal incorrect panel dimensions.

Optionally follow outside changes and connections

Once the basic match works, return to Advanced UI Scale Matching Settings… if you want changes made by macOS or another app to start matching too.

  1. Enable Watch for resolution changes made outside of the app. It starts off. Keep the same single watched display.
  2. If newly connected affected displays should be matched to that source, enable the now-visible Enforce UI scale match upon connecting a display. It also starts off.
  3. Leave Treat newly connected displays as possibly watched displays off for this setup. Enable it only if a connecting display should itself be considered as a source under your watched-display rules.
  4. Select Done. After BetterDisplay has finished startup, test the next outside resolution change or an intended affected display's reconnection and repeat the result checks above.

These switches apply to future changes or reconnections. Turning them on does not perform an immediate match. Multiple watched displays can propose conflicting modes for the same target, in which case that target is skipped. One watched source avoids that ambiguity.

Troubleshooting

Nothing changes

First confirm that the group is active, matching is enabled, the source is watched, and the target is a connected member selected under Affected displays. Choosing an already suitable mode can leave the target unchanged. For outside changes, check the outside-watch switch. Matching on reconnection also needs its own switch.

A mirrored target or a display with resolution protection is skipped in the initial setup. If you deliberately want the match to replace a protected resolution, record the exact old target first and enable Update resolution configuration protections. Successful app mode changes update existing saved resolution and refresh-rate targets. Re-enabling a protection captures the current value instead of retrieving the old target. See Configuration Protection.

The sizes are still different

Recheck the actual image-area dimensions on both displays and keep app zoom unchanged during comparison. Review the available target modes at its current refresh rate and bit depth. If none is close enough, use the flexible-scaling setup where supported or choose a different comfortable source size. Increasing tolerance cannot supply a missing mode.

If another group also matches these displays, inspect its watched and affected lists before changing more settings. Overlapping active groups can broaden the affected set and matching choices. Keep one predictable matching rule for the first test.

Undo or stop matching

  1. Turn Enable UI scale matching off in the group to stop this feature. Disabling the entire group also stops it, but stops that group's other features as well.
  2. Restore each display's recorded mode, HiDPI state and refresh rate. Turning matching off does not revert resolutions already selected.
  3. If protection values changed, temporarily turn off only the relevant Resolution or Refresh Rate protection, select the exact originally protected mode or rate, and re-enable that protection. Verify its saved value. Leave protections off if they were originally off. Selecting another mode while a protection is enabled can replace its target again.
  4. Restore any physical-dimension fields you edited to their original explicit values or empty state. Re-entering a visible fallback number is not the same as clearing a previously empty field.
  5. Restore any existing group activation settings you changed. To remove the temporary group, select Settings > Groups > UI Size > Discard…, then confirm Discard. Do not discard an existing desk group just to stop matching.

If the original protected mode is unavailable, leave that protection off and keep its target in your notes. Also leave it off if the original active mode and protected target differed and you want to keep the active mode. Normal menu changes can replace an enabled target. If you added flexible-scaling modes during preparation, keep them unless you also want to undo that separate setup.

Additional information

This section explains the license and platform requirements for the matching setup.

Features requiring Pro license

UI scale matching, manual Match Group UI Scales, watched and affected selections, tolerance, protection updates and outside-change/connection matching require Pro or an active trial, including in the Default Group. Activating a custom group also requires Pro. Physical-dimension editing is not separately Pro-gated.

Platform compatibility

This matching workflow is available on both Apple silicon and Intel Macs. The documented app requires macOS 26.3 or later. Each participating display needs accurate dimensions and suitable modes. Flexible scaling has its own display and activation requirements. UI Scale Matching works independently of brightness controllers. It does not need an administrator helper or Screen Recording permission.