Touchscreen test

Drag your fingers across the panel below. Anywhere the trail breaks or never appears is a spot your screen is not registering.

Drag one or more fingers across the panel. Full screen is better for checking the edges.

Drag here

Touching now
0
Most at once
0
Max touch points
—
Pressure
—

Touch coordinates stay in the page and are drawn straight to a canvas in your browser. Nothing is recorded or uploaded.

How to test a touchscreen properly

  1. Press Test full screen so the whole panel is available.
  2. Drag one finger slowly in overlapping horizontal lines from top to bottom, covering everything.
  3. Do the same vertically. Some dead zones only show up in one direction.
  4. Pay attention to the outer few millimetres and the corners. Edge damage is by far the most common, and it is the area you never test by accident.
  5. Then put five fingers down at once and watch the counter, adding more if your device supports them.

A healthy screen gives an unbroken trail everywhere. Gaps, jitter, or a line that jumps sideways all point at the digitizer.

The digitizer is not the display

A touchscreen is two components bonded together: the display that produces the image, and a transparent grid of electrodes above it that senses your finger. They fail independently. This is why a screen can look flawless and ignore touch in one corner, and equally why a cracked screen can still register touch perfectly.

It matters for repairs. On many devices the two layers are laminated into one assembly, so a digitizer fault means replacing the whole screen. On others they separate, and the repair is far cheaper. Knowing which part has failed tells you which quote is reasonable.

Reading the numbers

  • Touching now — how many contacts the browser currently sees. Put down four fingers and it should read four.
  • Most at once — the highest number reached in this session. This is the figure to compare against your device specification.
  • Max touch points — what the browser reports the hardware can handle. Some browsers cap this at ten even on panels that support more.
  • Pressure — how hard the contact is, between 0 and 1. Most touchscreens do not measure real pressure and report a flat 0.5 or 1; only pens and force-sensitive panels give meaningful values here.

Before you conclude the screen is broken

Several everyday things imitate a hardware fault, and all are worth eliminating first:

  • The screen protector. Thick glass, a bad fit or trapped bubbles all weaken response near the edges. Take it off and retest.
  • Moisture and grease. Capacitive screens read the electrical field around your finger, and a film of water or sweat spreads it. Clean and dry both screen and hands.
  • The charger. Poor-quality chargers inject electrical noise that produces ghost touches. Test on battery to rule it out.
  • Cases with magnets. Some interfere with the panel near the edge where the magnet sits.
  • Very cold or very hot conditions. Touch response degrades outside the operating range and recovers on its own.

If a dead zone survives all of that, it is the digitizer. Photograph the test result with the gap clearly visible — it makes the conversation with a repair shop much shorter.

Frequently asked questions

How many fingers should my screen detect at once?

Most modern phones and tablets track five or ten simultaneous touches, and many laptop touchscreens handle ten. The number your browser reports is shown as "Max touch points" below. If the live count stops climbing well before that figure, either the extra fingers are too close together or the digitizer is struggling.

One area of the screen does not respond at all.

That is a dead zone in the digitizer, the transparent touch-sensing layer bonded over the display. It is a separate component from the picture itself, which is why a screen can show a perfect image and still ignore your finger. Dead zones follow drops, pressure damage and liquid ingress, and they do not heal.

My screen registers touches I never made.

Ghost touches usually come from a failing digitizer, a damaged or poorly seated ribbon cable, or electrical noise from a low-quality charger. Try it unplugged first: if the phantom input stops while on battery, replace the charger before suspecting the screen.

Could my screen protector be the problem?

Yes, and it is worth ruling out early. A thick or badly fitted protector, or trapped air bubbles near the edge, can weaken touch response in exactly the patchy way a failing digitizer does. Peel it off and run the test again before spending anything on a repair.

Does this work with a stylus?

Yes. The test uses pointer events, so an active pen appears alongside finger touches and reports pressure where the hardware supplies it. Note that many devices deliberately ignore finger touches while a pen is near the screen, which is palm rejection working correctly rather than a fault.

Can I use this on a desktop with a mouse?

It will draw, but it tells you nothing useful — a mouse is a single pointer with no pressure or contact area. This test is meant for phones, tablets and touchscreen laptops.

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