Touch screen test: check multi-touch and dead zones
Swipe across the area with one or more fingers. Each finger gets its own color and touched cells are marked – gaps in your trails show spots where the touch screen does not respond.
How it is calculated
How to test your touch screen
- Tap “Fullscreen” so the test area fills the whole screen.
- Dead zones: swipe slowly in lanes across the entire screen with one finger. Touched cells change color; if a gap remains along your trail, the screen did not respond there.
- Multi-touch: place several fingers at once. “Most at once” shows how many touches the device reports in parallel.
- “Start over” clears the trails.
How it works
The tool uses Pointer Events (a W3C standard): every touch reports its own ID and position. The area is divided into small cells and every touched cell is marked. Between two reported points of the same trail, cells are only filled in if they are close – if the trail jumps over a larger gap, it stays visible.
Limits
- How many fingers are recognized at once depends on device, operating system and browser; some browsers reserve multi-finger gestures for their own features.
- Edges where the system handles swipe gestures (e.g. the back gesture) often do not pass touches to the web page – that is not a defect.
- A gap can also come from swiping too fast. Only treat a spot as faulty if it stays empty repeatedly when you swipe slowly.
Frequently asked questions
How do I test my touch screen for dead spots?
In fullscreen, swipe slowly in lanes across the whole screen. If cells along the trail stay empty repeatedly, the screen does not respond there.
How many fingers does my display recognize?
Place several fingers at once. “Most at once” shows how many touches the browser reported in parallel.
Why does the edge not respond?
Many systems use the edges for their own swipe gestures and do not pass those touches to web pages. That is usually not a hardware fault.
Does the test work with a stylus or mouse?
Yes, Pointer Events also report stylus and mouse. The multi-touch test needs a touch screen, though.
Is anything stored?
No. The trails only exist while the page is open and are not sent anywhere.
Sources and legal basis
- MDN Web Docs – Pointer events
- W3C – Pointer Events Level 3
- MDN Web Docs – Touch events: multi-touch interaction
- MDN Web Docs – Fullscreen API
As of:
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