About overscan and underscan
Overscan is when the margins of the picture are hidden beyond the borders of the screen, as if the picture is zoomed in.
Underscan is usually seen as pillarboxing or letterboxing: bars appear on the sides of the picture, or above and below it. This preserves its aspect ratio, so that you can see the whole picture.
Check settings on your Mac
Follow these steps while your TV or projector is showing content from your Mac:
- Choose Apple menu > System Settings (or System Preferences).
- Click Displays.
- In Display Settings for the TV or projector, look for a setting named Underscan.
- If the setting is available for your TV or projector, you can use it to adjust picture size.
- If the setting is not available for your TV or projector, it might help to choose a different display resolution.
- If these settings don't help, check the settings on your TV or projector instead.
Check settings on your Apple TV
On Apple TV 4K or Apple TV HD, go to Settings > AirPlay (or AirPlay and Homekit) > AirPlay Display Underscan.
On Apple TV (3rd generation) or Apple TV (2nd generation), go to Settings > Audio & Video > Adjust for AirPlay Overscan.
Check settings on your TV or projector
Most TVs and projectors offer picture settings that you can access using buttons on the remote, TV, or projector. Look for names like underscan, zoom, aspect ratio, presentation mode, computer mode, screen fit, screen fill, or format. For help, check the manual for your TV or projector, or contact the manufacturer.