Touch Screen Test
Draw mode splits the test area into squares of about 40 pixels and fills each one your finger reaches, so a square that stays empty is a spot that does not respond. Multi touch shows each finger as a numbered circle.
How to use
- In Draw mode, drag one finger slowly across the test area. Every square your finger reaches fills in. Cover all squares to finish; a square that will not fill is a spot that does not respond.
- Switch to Multi touch and put several fingers down together. Each touch shows as a numbered circle with its position, and the counter keeps the highest number of simultaneous touches.
- Press Full screen to test the whole display, edges and corners included. Press Reset to start over.
How it works
The test area is split into squares of about 40 pixels. A square counts as touched only when the browser reports a real pointer event inside it, so a spot that never reports a touch stays empty.
Coverage is filled squares divided by all squares, shown in percent. It reaches 100% only when every square has been touched.
Fast swipes can skip a square without a fault, so move slowly over any empty square before you blame the screen.
FAQ
How many touch points should my screen support?
Most modern phones and tablets track 5 to 10 touches at once, and many touch monitors track 10. A budget panel may stop at 2 to 5. Two fingers are enough for pinch zoom.
What causes a dead zone on a touchscreen?
A cracked or delaminated glass layer, a loose display cable, a poorly fitted screen protector, moisture, or a failing touch controller. Remove the case and protector and test again to rule out the cheap causes first.
Why does the page not go full screen on my iPhone?
Safari on iPhone does not allow the Fullscreen API for web pages. The tool then covers the whole viewport with the test area instead. Add the page to your home screen to hide the browser bars as well.
Does it work with a mouse or a stylus?
Yes. The tool uses pointer events, so a mouse, a pen and a finger all draw. Touch is the intended input, and the multi touch count only goes above 1 with real fingers.