Touchscreen Test

How it works

1. Touch the Test Surface. Tap, swipe, and hold on the box with one or more fingers. Each cell you touch lights up, and a progress line counts how much of the surface you've covered.
2. Sweep in Full Screen for the True Edges. The inline box only ever covers whatever area the page itself occupies. Switch to the full-screen sweep to reach your display's true edges instead of just this box — your last full-screen result is kept even after you exit.
3. Try Multiple Fingers at Once. Place two or more fingers on the surface at the same time to see how many simultaneous touches your browser actually reports back, compared with what it claims to support.
4. Check Hold Steadiness. Hold one finger as still as possible and run the steadiness check — it watches how far the reported position wanders while you're not moving on purpose.
5. Watch for Ghost Touches. Run the hands-off check without touching the screen at all — it watches for spurious touches a failing digitizer can register on its own.
6. Review Contact Details. Check whether your device reports real pressure and contact-size data, or only ever the flat default values most touchscreens without those sensors send.

Why This Tool Won't Show You Touch Latency or Millimeter Accuracy

No web API timestamps the exact instant your finger physically touched the glass — the timestamp your browser hands over is created later, once the touch has already passed through the operating system's own input pipeline. Measuring true latency would need a high-speed camera pointed at your screen, not a web page. Millimeter accuracy has the same problem from a different angle: no browser API reports your screen's physical size, only its resolution in pixels, so there's no way to convert a pixel offset into a real-world distance.

Why the Coverage Sweep Won't Catch Every Kind of Dead Zone

This test can only see what reaches the browser through the page itself. The inline box only ever covers the fraction of the display the page occupies — the full-screen sweep reaches much further, right up to your display's real edges, but even there your device's status bar, on-screen navigation gestures, notch, and rounded corners sit outside what any web page can ever detect. So an unlit cell near the very edge of either surface may simply be outside what this tab can reach — not proof of a hardware fault.

• You genuinely haven't swiped across that spot yet — the simplest explanation, and the most common one.
• You're using the inline box instead of the full-screen sweep, which can only ever reach the fraction of the display the page itself occupies.
• The browser intercepted the touch as a system gesture (like a screen-edge swipe) before the page ever saw it.
• That part of the surface sits under browser chrome, a notch, or a rounded corner this page cannot reach, even in full screen.

Multi-Touch: What "Claimed" vs. "Observed" Really Means

Your browser reports a maxTouchPoints number up front — its own claim about how many simultaneous touches your hardware supports. This test tracks the largest number of fingers it actually saw touching at once, separately, and compares the two. A result below the claimed number often just means you haven't tried enough fingers at once yet, or that your phone's operating system caps concurrent touches lower than the digitizer itself allows.

A result ABOVE the claimed number is also real, and worth knowing: some browser and OS combinations under-report maxTouchPoints even on hardware that genuinely supports more simultaneous contacts than advertised.

Hold Steadiness: The Touch Equivalent of Stick Drift

A healthy touchscreen should report a held finger's position within a fraction of a pixel of where it started, the whole time it's down. This test asks you to hold one finger as still as you can and watches how far the reported position wanders from where it settled, ignoring the very first fraction of a second — a finger's contact patch is still growing right after it lands, and that settling motion isn't a defect.

• Steady — no meaningful wander detected once the contact settled.
• Some wander — normal on many capacitive panels under a slightly damp or warm finger.
• Unstable — noticeably more wander than a steady hold should show.

Ghost Touches: What a Failing Digitizer Looks Like

A ghost touch is a contact your screen registers with nobody actually touching it — the touchscreen equivalent of a stuck key. This test asks you to leave the screen alone for about 20 seconds and counts any touch it sees during that window, ignoring the very first moment (the tail end of the tap that started the check, not a phantom one).

Pressure and Contact Size: Reading a Sensor That Might Not Exist

The web's Pointer Events API always includes a pressure value and a contact width/height on every touch — whether or not your actual hardware has a way to measure either one. On a touchscreen with no real force sensor, pressure comes back as a flat, unchanging value on every single touch. This test watches for that: if the number never actually varies across many samples, it reports "no pressure sensor" honestly instead of printing a fake, unmoving reading as if it meant something.

Contact size works the same way — a device with no real touch-geometry sensor reports a fixed 1×1 pixel point on every touch, and this test calls that out rather than pretending your finger is genuinely one pixel wide.

Nothing Is Uploaded

Every measurement on this page — where you touched, how many fingers at once, how steady a hold was, whether any ghost touches appeared, pressure and contact size — is read directly from your browser's own touch events and processed entirely inside this tab. Nothing about how you touch the screen is ever sent anywhere.

Frequently asked questions