Which test to use
The three touch tests each answer one question about the touch layer of a phone, tablet or touch laptop.
The touch screen test asks whether every part of the screen responds. It covers the display with a grid, and each cell you swipe over lights up. When you have crossed the whole screen, any cell that stayed dark is a spot the digitiser did not register. You can choose large, medium or small cells; small cells take longer but find a narrow dead strip, which is the typical damage after a drop.
The multi-touch test asks how many fingers the screen can track at the same time. Every finger gets a numbered ring that follows it, and the page keeps the highest number seen at once. Most modern phones track ten points, and the test shows what your browser actually receives. It is also useful for games and drawing apps that need two or three fingers.
The ghost touch test asks whether the screen touches itself. You pick thirty seconds, one minute or five minutes, take your hands off, and every touch the screen reports while nobody is touching it gets a mark and a timestamp. A clustered group of marks in one place usually points to hardware damage, while touches scattered across the screen often come from a charger or moisture.
How to get a reliable result
Wash and dry your hands and wipe the screen: water and grease cause both missed touches and phantom ones. For the ghost touch test, place the device on a flat, dry, non-metal surface and unplug the charger, because a cheap or faulty charger is the most common cause of ghost touches. Turn off any gesture or accessibility features that react to touches, and keep the screen awake during the run.
When to take it further
A dead zone that appears in the same place every time, or ghost touches that continue with the charger unplugged and the protector removed, is a hardware fault. On a new device, that is a reason to return or exchange it. On an older one, the usual fix is replacing the screen assembly, because the touch layer and the glass are bonded together. Keep a screenshot or a photo of the result to show the service centre what happened.
Frequently asked questions
Can I run the touch tests on a laptop without a touch screen?
No. The page checks whether the browser reports a touch screen before it loads a test, and on a device without one it shows a short note instead. A touch pad or a mouse does not produce touch events. Open the page on the phone, tablet or touch laptop you want to check.
What is the difference between a dead zone and a ghost touch?
A dead zone is a part of the screen that ignores your finger: you touch it and nothing happens. A ghost touch is the opposite, a touch the screen reports when nobody is touching it. They have different causes and different tests: the touch screen test finds dead zones, the ghost touch test logs phantom touches.
Does a screen protector affect the results?
It can. A thick tempered glass protector, a bubble or a lifted edge can create a dead zone near the edges, and a cracked protector can trigger ghost touches. If a test fails, take the protector off, clean the glass and run the same test again before you suspect the digitiser.
Why does the phone vibrate or open menus during the test?
The tests take over touches inside the page, but the operating system still reacts to its own gestures, such as swiping from the very edge to go back or pulling down the notification shade. Start swipes a finger's width away from the edge, and use fullscreen where the test offers it.