Guide · Touch Screen Test
How to test your touch screen for dead zones
Updated · 6 min read
A touch screen that ignores taps in one corner, types letters you did not press or reacts late is hard to describe and easy to measure. A grid test shows which parts of the display respond. This guide explains how to test a touch screen, what the result means and which fixes are worth trying.
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The touch screen test fills a grid as you touch it, so any area that does not respond stays empty.
- Open the test on the device you want to check and press Start fullscreen test.
- Drag one finger slowly across the screen in rows, then along the edges and into each corner.
- Continue until every cell is filled.
- Note any cells that do not fill, and whether they are always in the same place.
What a dead zone means
A dead zone that appears in the same place every time points to a fault in the digitizer, the layer that senses touch, or to a cracked screen or a loose connector. A dead edge is often caused by a thick case or a screen protector that does not sit flat.
If different cells fail at different times, the fault is more likely software, interference or a dirty screen. Retest after cleaning and after removing the case and protector to see which it is.
Ghost touches and typing by itself
A ghost touch is a tap that registers when nobody is touching the screen. Common causes are moisture, a cracked panel, a poor third-party charger that adds electrical noise and a protector with air bubbles. If the problem only happens while charging, try the original charger and a different cable.
Fix a slow or unresponsive touch screen
Start with the cheapest steps, and work toward the more disruptive ones.
- Clean the screen with a slightly damp microfibre cloth and dry your hands.
- Remove the screen protector and test again to see whether it is the cause.
- Restart the device. Many touch glitches are cleared by a reboot.
- Update the operating system and any manufacturer touch firmware.
- Boot into safe mode to check whether a third-party app is interfering.
- Back up your data, then reset settings. A factory reset is a last resort before repair.
When the screen needs repair
If dead zones remain after a restart, with the case off and the original charger, the panel or its connector is likely damaged. A repair shop can usually replace the display assembly, and your warranty or insurance may cover it. Run the test again after the repair to confirm the whole grid works.
Check how many fingers it can follow
Once single touch works, check pinch and zoom with the multi-touch test, and read the multi-touch guide to understand what the number of touch points means.
FAQ
Common questions
How do I test my phone screen for dead spots?
Open the touch screen test, press Start fullscreen test and drag your finger across the whole screen. Cells that do not fill are dead zones.
Why is my touch screen not responding in one area?
It can be a damaged digitizer, a loose connector, a cracked panel or a screen protector that is not flat. Test with the case and protector removed.
What are ghost touches?
Ghost touches are taps the screen registers without any contact, usually from moisture, damage or electrical noise from a poor charger.
Does the test work on a laptop touch screen?
Yes. Any device with a touch display and a modern browser can run it.