🫳Touch screen test

✓ Tested & verified Updated: Aug 11, 2026 How the test works

Touch screen test

Drag a finger across the whole surface, then put several fingers down at once. Scrolling and zooming are switched off inside this box so the panel reports every contact.

Fingers seen at once

0touches

Most phones report five, most laptops report ten. A screen that stops counting at two while you have three fingers down is a digitiser limit, not a broken panel.

Dead spots—
Surface covered—
Pressure—
Contact size—

Drag right into the corners and along the edges — that is where a digitizer fails first, and where a quick swipe never goes.

Try also

How do I test a touch screen?

The Devicedial touch screen test tracks every finger on the glass at once and reports two things: how many the panel registers simultaneously, and whether any part of the surface failed to respond.

Drag slowly over the whole screen, corner to corner and along the edges. Every point the browser receives is drawn, so a gap in the trail is an area the digitizer did not report — the signature of a cracked panel or a failing controller.

The touch count is the second half. Put five fingers down together and count what appears: most phones stop at five and most Windows touchscreens at ten, which is a hardware and driver limit rather than a fault. Where the browser reports them, contact size and pressure appear next to each pointer, though most panels return a flat 0.5 and a contact box of exactly 1 by 1, which means the hardware measures neither.

Half of what a touch screen reports is a default value standing in for hardware that is not there. These are the readings you will see and what each one is actually telling you.

Reading	Typical value	What it tells you
Simultaneous pointers	5 on phones, 10 on Windows	the panel and driver limit, not a fault
`pressure` while touching	exactly 0.50	no force sensor — this is the fixed default
`pressure` varying	0.05 to 1.00	real force reporting, usually a pen
`pressure` mid-stroke	0.00	contact was lost, or the pointer is hovering
`width` × `height`	1 × 1	contact geometry not measured by the device
`width` × `height`	20 × 25	the contact patch in CSS pixels, grows as you press
`pointerType`	touch, pen or mouse	which input really generated the event

A screen that reports a flat 0.50 and a 1 by 1 contact box is not broken. It is a perfectly ordinary capacitive panel that reports position only, which is all the vast majority of them do.

The rest of the display is worth checking while you are here: dead pixel test for the panel underneath the digitizer, screen resolution for the pixel grid your finger is pointing at, and the mouse tester for the same job on a pointer with buttons.

Frequently asked questions

Why does my phone only register five touches?

Because five is what the platform reports as its maximum, and the browser will not invent a sixth. Apple’s mobile browsers cap at five, most Android phones report five or ten, and Windows touchscreens usually report ten. It is a property of the digitizer and its driver, not a fault, and no browser setting raises it.

Why does nothing happen when I use a mouse?

A mouse is a single pointer, so it can draw a trail but never demonstrate multi-touch, and a desktop monitor without a digitizer reports zero touch points before you even start. The test accepts touch, pen and mouse input alike, but only a touchscreen or a pen-enabled display can answer the questions this page is asking.

What does a pressure reading of 0 mean?

It means the pointer is not in contact — a pen held above the glass, or a mouse moving with no button down. Hardware with no force sensor does not report 0 while you touch it; the specification tells it to report exactly 0.50 instead. So a flat 0.50 means no pressure hardware, and a 0 mid-stroke means contact was lost.

How do I tell a cracked digitizer from a software fault?

By whether the dead area moves. A hardware fault sits in the same place every run, usually as a straight band, survives a restart and shows up in every app including this page. A software fault wanders, appears in one app only, produces ghost touches where nothing is touching, or clears after a reboot or in safe mode.

Why do gloves or a screen protector change the result?

Because a capacitive panel senses a conductive object disturbing an electric field, not physical force. Most gloves insulate, so the field barely changes and the touch never registers. A thick or badly fitted protector, or trapped air and moisture under one, adds distance and weakens the same signal. Some phones ship a high touch sensitivity setting that compensates.

Why does the trail lag slightly behind my finger?

Because pointer events are delivered to the page once per frame while the panel scans faster, so several real samples arrive together and the line is drawn to the newest one. Browsers expose the intermediate positions that were folded into each event, which recovers the shape of the stroke, but the delay itself belongs to the display pipeline.

How the test works

The test listens to Pointer Events rather than touch or mouse events, so one code path covers a finger, a pen and a mouse. Each contact carries a pointerId that stays with it from pointerdown to pointerup, so the number of live ids at any instant is the number of touches the panel is genuinely reporting — measured, rather than read from navigator.maxTouchPoints, which is only what the platform claims it can do. The drawing surface sets touch-action: none, otherwise the browser treats your stroke as a scroll or a pinch, takes the gesture for itself and fires pointercancel halfway through the test.

Dead zones are found by dividing the surface into cells and marking every cell a pointer passes through; a cell that stays unmarked after you have covered it is reported as unresponsive. pressure is read on the 0 to 1 scale, where 0.5 is the fixed value hardware without a force sensor must return, and width and height describe the contact patch in CSS pixels, defaulting to 1 when the device cannot measure it. One thing this page cannot tell you: the panel’s hardware sampling rate. Events are delivered at the browser’s frame cadence, and even the coalesced intermediate points are a browser-side figure, not the digitizer’s scan rate.

Sources:

What a touch screen actually senses

Not pressure — capacitance. A grid of transparent electrodes under the glass holds a small charge, and a finger disturbs it. That is why a fingertip works, a gloved finger often does not, and a plastic stylus never does unless it is built with a conductive tip.

Contact area stands in for force. Press harder and the fingertip flattens, so the disturbed patch grows. Panels that report contact width and height are describing that patch, which is why the numbers grow as you press even on hardware with no force sensor at all.

The edges fail first. Electrode traces run to the panel’s connector along the borders, and both impact damage and flex fatigue concentrate there. A test that only swipes across the middle of the screen will miss the fault that is about to spread.