Tap Start, then drag a finger over the grid, and any patch of screen that does not respond stays blank.
The number of touch points your device reports shows here.
Touch the screen to start.
Filled 0 squares
On a touch screen, Start opens the grid over the whole screen. Hold Done for a second to come back.
Label the next run
More options
Your last five runs
No run yet.
Nothing from this test is stored unless you tick the box. Kept runs are numbers only and never leave this browser.
How this check works
Grid fill, whole screen
The screen becomes a grid of squares. Drag one finger over all of them, like colouring in, and each square fills as the touch passes through it. A patch that does not respond stays blank. The result is a count: 3 of 240 squares stayed blank.
A square fills only where the screen reported a touch. The page shows what arrived, and it never judges the screen.
A square of the grid fills only when the screen reports a touch inside it.
A square that lies between two reports but got none of its own is marked as passed over, not filled.
The finger count is the most touches the browser reported at one moment, next to the number the device says it supports.
Border trace, edges and cornersOnly the outer ring of squares counts. A case or a lifting screen protector gets in the way at the edges first, and system gestures live there too. Trace the border slowly with one finger, all four sides.
Fast strokes, edge to edgeSwipe quickly across the full width, then the full height, a dozen times. A touch that drops out for an instant shows as a gap in the stroke. Each stroke ends in a round dot where you lifted, so an end in mid-screen is easy to spot.
Finger count, up to 10Put fingers down one at a time. A numbered ring appears under each touch, and the page keeps the most it saw at once. Beside it is the number of touch points the device itself claims, which is typically 5 on a phone.
Grid fill, whole screenThe screen becomes a grid of squares. Drag one finger over all of them, like colouring in, and each square fills as the touch passes through it. A patch that does not respond stays blank. The result is a count: 3 of 240 squares stayed blank.
Show all 20 checks (16 more)
Touch checks, one at a time, continued
Pen strokes with pressureFor a stylus that the device recognises as a pen. The line grows thicker as you press, using the pressure figure from 0 to 1 that the pen reports. A plain rubber-tipped stylus usually counts as a finger and draws at one width.
Same grid on battery, then on the chargerRun the grid or the diagonals unplugged, then plugged in, and compare. A noisy power supply can disturb a capacitive screen for as long as it is connected. The page cannot see your charger, so you label the two runs yourself.
Screen left alone for 15 secondsLay the device flat, take your hands away and watch. Any touch that arrives is one you did not make, and the page marks where it landed. Several in one spot say more than one stray.
Slow diagonals, corner to cornerDraw a straight line slowly from one corner to the opposite one, then the other diagonal. The page draws exactly the points the screen reports, with no smoothing. Your eye knows what a straight line looks like, so wobble and stair steps stand out.
Touch readings that need a second look 12
A blank strip along the top or bottomThe browser's bars and the system's swipe zones sit there, and touches on them never reach a page. Go full screen if the button is offered. If it is not, rotate the device so that strip moves into the middle of the grid.
A finger count that stops at 1 or 2Compare with the number the device reports. Resistive screens, the kind you press, are mainly single touch by design. On a capacitive screen that reports 5 or more, a count stuck at 2 deserves a second run with dry, bare fingers spread well apart.
A stroke that breaks in the same place each timeOne gap is chance. A gap at the same spot on five strokes in a row is a pattern. Draw through it from another direction, then run the grid over that area. Note the position in case you need to describe it to a repairer.
A stroke with a square endA square end means the browser cancelled the touch, usually because it decided the movement was a scroll, a zoom or a system swipe. The screen did its job. A round end means the touch itself lifted or was lost.
The device reports 0 touch pointsThe browser says this device has no touchscreen, which is the normal answer on a desktop computer. You can still fill the grid with a mouse to see how the page works, and it labels that run as mouse input.
Every touch cancelled as another finger landsThe browser or the system has claimed a gesture made with several fingers and taken the touches away from the page. Look for a multi-finger gesture setting, or stay under that number. It is software, not the panel.
Five counted with ten fingers downNormal on a phone. Smartphones typically report a maximum of 5 touch points, and the page cannot count more touches than the device tracks.
Nothing registers through glovesCommon on a capacitive screen, though not on every one. It senses the change a conductive finger makes to its electric field, and ordinary cloth insulates. Gloves with conductive thread in the fingertips, or a capacitive stylus, get through.
Squares shown as passed over, not filledYour finger moved faster than the screen reported it, so the page saw points on either side of a square and none inside. That is speed, not a dead zone. Cross those squares again slowly and they should fill.
Squares that stay blank on every passWipe the glass, take off the case, and run the grid twice. Then rotate the device and run it again. A blank patch that stays on the same piece of glass in both rotations suggests the touch layer there. One that moves with the rotation belongs to the browser or the system.
Touches with no finger on the glassWipe the screen, unplug the charger and switch off any glove or high-sensitivity mode, which is documented as a source of phantom input. Then repeat the 15-second watch. Touches that keep landing in one spot are the ones to note.
Two fingers side by side read as oneA touch layer is a grid of crossing traces, and the more crossings it has, the finer the detail it can resolve. Two touches closer than its grid can merge. Spread the fingers a little and the second ring should appear.
How this list was compiled: Table written for this page. That the browser reports the greatest number of simultaneous touch points a device supports, that computers without a touchscreen return 0 and that smartphones typically return 5, is from https://developer.mozilla.org/en-US/docs/Web/API/Navigator/maxTouchPoints (page last modified 8 April 2026, checked 2026-09-19). That a browser cancels a pointer when it decides to treat the movement as a pan or zoom, that the touch-action property set to none switches that default handling off for a region, that a touch is the primary pointer when it lands with no other touch active, and that width, height and pressure describe the contact (pressure from 0 to 1) are from https://developer.mozilla.org/en-US/docs/Web/API/Pointer_events (checked 2026-09-19). Browser support was read on 2026-09-19 from https://github.com/mdn/browser-compat-data: api.Navigator.maxTouchPoints and api.PointerEvent in api/Navigator.json and api/PointerEvent.json (Chrome 35 and 55, Firefox 59, Safari 13), api.PointerEvent.getCoalescedEvents (Chrome 58, Firefox 59, Safari 18.2), css.properties.touch-action (Chrome 36, Firefox 52, Safari 13, Safari on iOS 9.3), and api.Element.requestFullscreen in api/Element.json, whose notes for Safari on iOS read: only available on iPad, not on iPhone; shows an overlay button which can not be disabled; swiping down exits fullscreen mode. That the body is a conductor and a touch distorts a capacitive screen's electrostatic field, that a glove with conductive thread or a capacitive stylus gets through, that a glove-sensitivity mode can result in unreliable and phantom inputs, that a noisy power supply can for a time upset the accuracy, precision and sensitivity of a capacitive screen, that mutual capacitance tracks several fingers at the crossings of a grid of traces and more crossings give better resolution, and that resistive screens need pressure, work with gloves or any rigid object and are mainly single touch, follow https://en.wikipedia.org/wiki/Touchscreen (checked 2026-09-19). On gloves that article says two things, and the table follows the more careful one: its opening says some capacitive touchscreens cannot sense a finger through an electrical insulator such as a glove, and its Glove touch section says capacitive touchscreens seldom work with gloves on (revision of 2026-09-05, read 2026-09-19). The page therefore says many screens, never all. The square size, the 15-second watch and the advice on each reading are this page's own, worded as suggestions and never as a verdict on a screen. No service-menu codes are given anywhere on this page. Licence: own work
How it works
This touchscreen test is a website: it checks a phone, tablet or laptop screen in the browser, with nothing to install. The touchscreen tester also counts fingers that register at once and draws your strokes as the screen reports them.
Read the full guide
Touch test: fill the grid, then look for blanks
For Grid fill, whole screen, press Start and drag one finger over every square. On a touch screen the grid opens over the whole screen. The run ends when all are filled, or when you hold Done for a second. The result is a count: 3 of 240 squares stayed blank. Rotate and run again: a blank patch on the same glass needs a second look.
Multi touch screen test, then draw lines
Under Check to run, Finger count, up to 10 puts a numbered ring under each touch. It keeps the most seen at once, beside the number your device claims to track. Phones typically report 5. Slow diagonals, corner to corner draws exactly the points the screen reports, so wobble, stair steps and gaps show.
Gloves off: many capacitive screens do not sense a finger through one, and a glove mode can add phantom touches.
Questions and answers
How do I find a dead zone with a touch screen test?
Fill the grid. Every square your finger crosses fills in, so an area that never responds stays blank. Wipe the glass, take the case off and run it twice. If the same squares stay blank in both rotations, note where they are.
Does it work as an iPad screen test?
Yes, for touch. On that tablet the grid can go full screen, though a downward swipe leaves it. On an iPhone, Safari offers pages no full screen, so the strips under the browser's bars go unchecked. Rotate the phone to bring them into the grid.
Why does a line stop while I am still drawing?
A browser that reads a movement as a scroll or zoom cancels the touch for the page. The drawing area switches those gestures off, and a cancelled stroke gets a square end. A round end that recurs in one place is the one to note.
How to test touch screen on a used phone?
Run the grid in both rotations, then the finger count, before you pay. Add the border trace: a case or a lifting screen protector gets in the way at the edges first.
Does this touch tester work with a mouse or a pen?
Yes. With no touchscreen, a mouse fills the grid and the run is marked as mouse input. In the pen check, a stylus the device recognises as a pen draws a line that thickens with pressure.