Device / Touchscreen
Touch Screen Test (Multi-touch and Dead Zones)
Test a phone or tablet touchscreen: see how many fingers it tracks at once, draw to check responsiveness, find dead zones with a grid, and test vibration.
Touch Screen Test (Multi-touch and Dead Zones): The test listens for pointer events from each finger separately, so every touch draws its own colour, and counts how many are active at once and the most at one time. The grid divides the area into 216 squares that turn green when touched; a square that stays blank after you drag over it points to a dead zone. Full screen mode tests the whole screen. Runs 100% locally in your browser with zero server file uploads.
- Category
- Everyday tools
- Runs
- In your browser
- Cost
- Free · no sign-up
- Availability
- Ready to use
Runs entirely in your browser
Put several fingers on the screen to see how many touches it tracks at once; most phones manage ten. In the grid test, drag a finger over every square: one that will not turn green points to a dead zone. Vibration works only on phones that support it, and not on iPhone in a browser.
Touch points now: 0; maximum simultaneous touches: 0.
Touch pressure is often unavailable. A reported 0.5 can be the browser's default for contact, not a force measurement. IDs last only for the current contact. A mouse can draw and mark the grid, but does not test multi-touch. An untouched cell is untested; repeat a careful pass before suspecting a dead zone.
Touch IDs and reported pressure
The contact labels show each active pointer ID, and the readout shows pressure reported by the browser. IDs identify a contact only while it remains active. A mouse can exercise drawing and the grid, but cannot verify multi-touch. Untouched grid cells are untested; repeat a careful pass before suspecting a dead zone.
Pressure is often unavailable; 0.5 can be the browser's default while a pointer is in contact, rather than measured force. W3C Pointer Events defines these defaults and pointer IDs: https://www.w3.org/TR/pointerevents3/#pointerevent-interface .
Reading the results
A line that breaks up, jumps, or lags behind your finger points to a faulty or dirty screen, a screen protector lifting at the edge, or a charger causing interference; try again unplugged. Touches that appear where you did not press, called ghost touches, usually mean damage or moisture.
If a whole strip of the grid stays blank, the digitiser may be damaged along that line. Check the display itself for dead pixels with the monitor test.
On a computer
On a touchscreen laptop the test works the same way. With a mouse or trackpad it shows a single pointer, which is still useful for checking that clicks and drags register everywhere.
To see what your browser reports about the device, such as screen size and touch support, use device info.
How to use it
- Put several fingers on the box to see how many touches are tracked at once.
- Draw lines to check for gaps or jumps.
- Switch to the grid and drag across every square to find dead zones.
Privacy & limitations
Everything runs in your browser; nothing is recorded or sent.
Related tools
Frequently asked questions
How many touches should a screen detect?
Most phones and tablets track ten; some cheaper screens and older devices track only two or five.
Why does the vibration button not appear?
Browsers on iPhone and iPad, and most computers, do not offer vibration to web pages.
Does this find dead pixels too?
No: for dead or stuck pixels, use the monitor test, which fills the screen with plain colours.
Free tool · runs in your browser · no account required