Touch screen test
Swipe your finger over the grid until every square lights up. A square that stays dark when you swipe it is a dead zone. Edges and corners matter most: that is where worn and cheap replacement screens fail first.
Open this page on the phone you want to test. Press Back or the close button to stop at any time.
How to do it
- Tap Start. The grid fills the whole screen.
- Swipe slowly over every square, row by row, right to the edges.
- At 100% the grid turns green. If squares stay dark, tap Finish: they turn red so you can try them again.
What the result means
- Every square lit: the touch layer responds everywhere.
- Squares stay red after several tries: that part of the touch layer is dead. Typing and swiping there will fail.
- Squares light up on their own: ghost touch, often after a crack or a cheap screen replacement.
What a browser cannot see: whether the phone is really the model it claims (copies run on a different processor), how worn the battery is, whether the storage is as big as it says, and whether the system was modified. The free Knowfone app for Android checks all of that and every part above in about 7 minutes, then answers: good to buy, buy only at a lower price, or don't buy.
Questions
Is there a code for the touch screen test?
On many Samsung phones *#0*# opens a test menu with a Touch grid; other brands use other codes (see the phone test codes guide). This online test works on any phone with a browser, without a code.
What is ghost touch?
The screen reacts when nobody touches it: apps open and letters type themselves. It usually comes from a damaged or poor replacement screen, sometimes from a bad charger. Here it shows as squares that light up while your finger is away.
Does this test work on an iPhone?
Yes, in Safari. iPhones do not let web pages cover the browser's own bars, so the thin strip under them cannot be tested here.
More phone tests
Buying a used phone? Read the 14-step checklist or look up the real specs of popular models.