How to use the touch screen test
- Press Start. The grid covers the screen.
- Slide your finger over the whole screen until every square fills, including the corners and the edges.
- Watch the counter: it shows what percentage of the screen has been tested.
- Put several fingers down at once. Most fingers at once shows the largest number the screen read together.
- Tap Done to leave.
Below the counters, the test shows how many touch points your screen reports to the browser, for example: This screen reports up to 10 touch points. That number comes from the device itself; the finger count is what you actually managed during the test.
What the result means
- Squares that stay empty while your finger clearly passed over them form a dead zone. Go over them again slowly: if they still do not fill, that area of the touch layer is not responding.
- A line of empty squares across the screen often follows a crack or a damaged connector, even when the glass looks fine.
- If Most fingers at once stays below what you put down, the screen is losing touches with several fingers. Compare it with the number of touch points the screen reports.
- Squares that fill by themselves, without a finger nearby, point to ghost touches.
Swipes from the very edge of the screen can be taken by the system: the back gesture on Android, the home and Control Center gestures on iPhone, and the edge swipes on Windows. If an edge square does not fill, start the swipe a little inside the screen and slide outwards.
Screen protectors, water and chargers
- Clean the screen and dry your hands. Water drops and wet fingers cause missed and ghost touches.
- A thick, cracked or badly fitted screen protector (dust, air bubbles, peeling edges) reduces touch response. Remove it and test again.
- Unplug the charger and test again. Some cables and chargers, especially cheap ones, cause erratic touches while the phone charges.
- Take off gloves and remove a case that presses on the edges of the screen.
- Restart the device. A frozen app or system bug can look like a dead screen.
Settings by system
- Samsung Galaxy: Settings > Display > Touch sensitivity raises the sensitivity for use with a screen protector. It is not available on every model.
- Android: to see every touch as a trace, turn on Developer options (Settings > About phone, tap Build number seven times; on Samsung it is under Software information), then turn on Pointer location in Developer options.
- iPhone and iPad: check that Settings > Accessibility > Touch > Touch Accommodations is off unless you set it up on purpose, because it changes how touches are read.
- Windows touch laptops: in Device Manager, open Human Interface Devices and check HID-compliant touch screen. If it is missing or has a warning, update or reinstall the driver. To realign touches that land in the wrong place, search the Start menu for Calibrate the screen for pen or touch input.
When it is a hardware fault
If a dead zone stays in the same place after cleaning, removing the protector and a restart, the touch layer or its connector is damaged. Write down the percentage and take a screenshot of the grid. On a new device, contact the store within its return period or the manufacturer under warranty; after a drop or water damage, the repair usually means replacing the screen.
Questions
How do I test my touch screen for dead spots?
Press Start and slide your finger over the whole screen. Squares fill where the screen responds; any area that stays empty after a second pass is a dead zone.
How many fingers can my touch screen detect?
The test shows how many touch points the screen reports and counts the most fingers it read at once. Put all your fingers down together to check.
Why don't the edges of my screen respond?
System gestures can take swipes that start at the very edge. Start a little inside the screen and slide outwards. If the edge still stays empty, check the case and screen protector.
Does the touch screen test work on iPhone and Samsung?
Yes. It runs in the browser on iPhone, iPad, Android phones and tablets, and on Windows laptops with a touch screen. Nothing is installed.