How to use
- Tap Start drawing test and slide one or more fingers across the screen. Check the trails are continuous and the touch count is right.
- Tap Start grid test and slide a finger over every cell.
- Tap Exit in the top corner to see the result.
Options explained
- Touch points
- How many fingers the screen detects at once. Most phones support 5–10. Fewer than advertised, or a trail that keeps breaking, can point to a screen or screen protector problem.
- Grid test
- The screen is split into 8 columns × 14 rows. A cell you slide over that stays blank received no touch.
How the two tests read your touches
In the grid test the full-screen area is divided into 112 equal cells, 8 across and 14 down. A cell is marked as soon as the browser reports a touch inside it, and the counter shows “Cells covered” out of 112. On a phone whose full-screen area is 390 × 844 CSS pixels, each cell is about 49 × 60 pixels, so you need to sweep your finger in lines roughly a finger-width apart, not just once across the middle.
Only the points the browser reports are marked, and the tool does not fill in the space between two reports. If you swipe very fast, the screen may report points that are further apart than a cell, and cells in between stay empty even though nothing is wrong with the screen. Move slowly, and judge a cell as dead only if it stays empty when you touch it directly, for example with a tap.
In the drawing test each finger gets its own trail colour, chosen from ten colours by the touch’s identifier. A new finger can therefore reuse a colour after ten touches. The top of the screen shows “Touch points” now and the maximum so far, and the result after you tap Exit is the highest number seen at once. The count comes from the browser, which gets it from the operating system, and some devices limit it regardless of the screen hardware.
Scrolling, zooming and pull-to-refresh are blocked while a test is open, and leaving full screen also ends the test.
Frequently asked questions
Why does a line break up while drawing?
The odd break can come from dry fingers or moving very fast. If it always breaks in the same place, the screen or its cable may be faulty. Try again without the screen protector to rule it out.
Can I test on a computer?
Only with a touch screen; a mouse does nothing here. Touch laptops and 2-in-1 tablets work.
Will the page scroll while testing?
No. Scrolling, zooming and pull-to-refresh are blocked during the full-screen test.
Privacy
This tool runs entirely in your browser. Your files and text are processed on your device and are never uploaded to our servers.