How to use it
- Press Full screen so the grid covers the whole display, then drag slowly across every square. Try horizontal and vertical passes.
- Any square that stays grey after several passes is a dead zone — usually a damaged digitizer or a crack, sometimes a bad screen protector edge.
- Put several fingers down together: Most at once shows how many your screen tracks (phones 5–10).
- Press Watch for ghost touches, put the device down and do not touch it. Any touch counted is a ghost touch: a failing digitizer, moisture, a charger with noisy power, or a bad protector.
Ghost touches: what helps
- Unplug the charger — cheap chargers are the number one cause of phantom touches while charging.
- Dry the screen and edges; remove the case and protector to test.
- Restart; update the OS; if it persists with the protector removed and unplugged, the digitizer needs service.
Related tests
Dead pixel testFull-screen colours, stuck pixelsScreen resolutionResolution, DPR, HDR, gamut, rulerMouse testButtons, scroll, double-click, Hz
Questions, answered
Can I test a laptop touch screen or a Surface?
Yes. Open the page in any browser on the device and press Full screen.
A row of squares at the very edge never paints.
Many phones ignore the outer few pixels to reject palm touches. Test with the grid in full screen; an edge strip is normal, a strip in the middle is not.