Dead Pixel Test
Fill the screen with five solid colors to spot dead, stuck and hot pixels.
Touch Screen Test
Drag a finger over every cell of the grid: cells that never fill show where your touch screen does not respond. Put several fingers down at once to see how many touches your screen and browser track together.
Showing 0 touches · 0% covered
- Touches now
- 0
- Most at once
- 0
- Total touches
- 0
- Coverage
- 0 / 0 cells (0%)
Works with a mouse too, which is handy for trying it out but does not test touch hardware. Edge strips reserved by the operating system may not paint.
Runs entirely in your browser. Test results, audio and video never leave your device.
How to test a touch screen
- Clean and dry the screen first. Water, grease and dirt can cause missed or false touches on a working screen.
- Press Start test. The grid fills the screen, or the browser window where full screen is not available.
- Drag one finger slowly over every cell, including the edges and corners. Painted cells turn blue, and the bar at the bottom shows the percentage covered.
- Put two, three or more fingers down together. Each touch gets a numbered, colored marker, and Most at once records the highest number held together.
- Press Exit or Esc when you are done. The grid from your run stays in the preview, with Coverage and the touch counts below it. A cell that is still black marks a spot to try again; Reset clears the grid.
What is a touch screen dead zone?
A touch screen dead zone is an area that ignores touches while the rest of the screen works. It usually comes from damage to the digitizer, the touch-sensing layer of the screen, or to its connector, and shows as a patch or strip where taps and swipes do nothing. Water, dirt or a badly fitted screen protector can cause the same symptom.
How many touch points does my screen support?
Most at once shows the most touches the browser reported at the same time. It can never be higher than the lowest of three limits: what the screen senses, what the operating system passes on and what the browser reports. A low number is not proof of a hardware fault, so try another browser before blaming the screen.
On Windows 11, iPad and some Android phones, system gestures that use three or more fingers can take over before the page sees every finger. Turn them off in the touch or gesture settings to count them all. Windows lists the screen’s touch points in Settings > System > About, under Pen and touch.
How to check for ghost touches
Ghost touches are taps or swipes a screen registers when nothing touches it. To check, lay a phone or tablet flat, press Start test and leave the screen untouched for a minute or more; set a longer screen timeout first so the display stays on. A marker that appears on its own, or a cell that turns blue while you are not touching the screen, is a ghost touch.
Ghost touches can come from a charger or cable, water or grease on the glass, a cracked or lifting screen protector, or a damaged digitizer. Test again unplugged, cleaned and without the protector: if the ghost touches stop, the screen itself is probably fine.
Testing a phone, tablet or laptop touch screen
Touch sensing works separately from the picture, so a screen can show a perfect image and still have a dead zone. When you check a used phone or laptop, run the Dead Pixel Test too, or the Monitor and Screen Test for a full check.
- Android, Windows and ChromeOS: in most browsers, Start test fills the whole screen.
- iPhone and iPad: browsers on iPhone, and some on iPad, cannot make a web page full screen. The grid then fills the browser window, so the areas covered by the address bar, toolbars and status bar cannot be tested.
- Laptops: a mouse or touchpad paints the grid too while you click and drag, but only finger touches test the touch screen. Check the touchpad with the Mouse Test.
- Stylus: the pen tip paints like a finger, so you can check that the pen registers across the whole screen. A pen hovering above the glass does not paint.
What this test can detect
- Dead zones: cells that stay black however often you drag over them.
- Touches that drop out mid-swipe: the marker disappears while your finger is still on the glass, leaving gaps in the painted path.
- Ghost touches: markers or painted cells that appear while nothing touches the screen.
- How many touches register at once, shown as Most at once.
- Touches that land in the wrong place: the crosshair lines meet away from your fingertip.
How it works
The page divides the test area into near-square cells of about 36 to 56 CSS pixels, sized so a whole number of rows and columns fills it. It listens for Pointer Events, which browsers send for fingers, pens and mice, and paints the cell under every position the browser reports, including the in-between positions it groups together during a fast swipe. A very fast swipe can still jump over a cell.
Each contact gets a numbered, colored marker with crosshair lines. Coverage counts painted cells out of the total and rounds the percentage down. A mouse or pen paints only while its main button or tip is down.
Limitations
- Operating systems keep some edge swipes for navigation, such as going back or opening notifications, so an edge strip may not paint with a swipe even on a working screen. Tap each edge cell before counting it as dead.
- Touch latency and sampling rate are not measured. The page receives touches only after the screen, the operating system and the browser have processed them, often grouped into display frames, so it cannot time the touch hardware.
- A fault that comes and goes may not show in one run, so test again when it happens, for example while charging. The page shows where touches fail or appear, not why.
- If the glass is cracked, do not drag a bare finger across it. Cover the crack with clear tape or use a stylus.
Frequently asked questions
Is there a touch screen test code for Samsung or Android phones?
Some phones have one. Many Samsung Galaxy phones open a hardware test menu with a touch test when you dial *#0*#, but availability varies by model, region and carrier, and iPhones have no such code. This page works in a phone browser without a code.
Can a touch screen dead zone be fixed?
Sometimes. Clean and dry the glass, remove the screen protector and restart the device, then test again. If the same area still ignores touches, the digitizer or its connector is usually damaged and needs a repair. No app or website can fix a hardware fault.
Can a touch screen test measure pressure?
No. This page reads where each touch is, not how hard you press or how a pen is tilted. A finger’s reading is not a force measurement; stylus pressure is on the Pen Pressure Test.
What is touch screen calibration?
Calibration lines up the point a screen registers with the point you touched. Phones and tablets are calibrated at the factory and usually have no setting for it; on Windows, some touch screens can be recalibrated from Tablet PC Settings in Control Panel. Here, the crosshair lines show where each touch lands.