How to test your touch screen
- Wipe the screen with a dry microfiber cloth and dry your hands. Water and grease cause missed and phantom touches.
- Press Dead zone grid test. The screen fills with a grid of squares.
- Swipe slowly over every square, right up to the edges and corners. Each square turns green when the screen feels your finger.
- When the whole grid is green, every part of the screen works. If some squares won’t turn green, press Done: the squares that never responded turn red.
- Press Multi-touch & drawing test and draw slow lines across the screen. Then put fingers down one at a time and watch the count.
- Press Done or Esc to close the test.
What the results mean
- The whole grid turns green: every area of the screen responds to touch. If an app still misbehaves, the problem is more likely the app or a setting.
- Red squares in a line or patch: a dead zone. Try those squares again slowly, and once more after the steps below. A dead zone that stays after a restart usually means the touch layer (the digitizer) is damaged.
- Broken or jumpy lines when you draw: the screen is losing track of your finger. A screen protector, dirt or a weak spot in the screen can all cause it.
- Circles or lines appear where you aren’t touching: ghost touches. Unplug the charger and test again, since a faulty charger or cable is a common cause.
- Fewer touches at once than you expect: some screens and drivers track only two or a few fingers. Compare with the reported number of touch points.
How to fix an unresponsive touch screen
- Clean and dry the screen. Remove any case that presses on the edges of the screen.
- Take off the screen protector if it is cracked, lifting or has bubbles, and test again. Thick glass protectors can make the edges less sensitive.
- Unplug the charger. If ghost touches stop, try a different charger and cable, preferably from the device’s maker.
- Restart the device. This clears a frozen touch driver or app.
- Check the settings:
- Samsung Galaxy: with a screen protector fitted, turn on Settings › Display › Touch sensitivity.
- iPhone and iPad: if touches behave strangely, check that Settings › Accessibility › Touch › Touch Accommodations is off.
- Windows touch laptops: open Device Manager, expand Human Interface Devices, right-click HID-compliant touch screen, choose Disable device and then Enable device. If touches land in the wrong place, search for “Calibrate the screen for pen or touch input” in the Start menu.
- Install updates for the system and, on Windows, the touch screen driver from the laptop maker.
- Rule out apps on Android. Many phones can start in safe mode, which turns off downloaded apps. If touch works there, an app is the cause.
- Get it repaired. If a dead zone or ghost touches remain after all of this, the screen or its connector is likely faulty. Contact the maker or a repair shop, especially while the device is under warranty.
Tips for an accurate test
- Use the device in the case and with the protector you normally use, then without them, to see whether they are the cause.
- Swipe slowly. A very fast swipe can skip past a square on some screens.
- Test with the screen upright and turned sideways, since some faults appear only in one direction.
- To check a stylus, draw with it in the multi-touch test. The Input used box shows Pen when the browser recognizes it.
Checking a screen for display faults instead? The monitor test finds dead and stuck pixels, and the screen resolution checker shows the size and scaling your device reports.
Is this test private?
Yes. Your touches are read and drawn by your browser on your device. Nothing is uploaded or stored.
Frequently asked questions
What is a touch screen dead zone?
A dead zone is an area of the screen that doesn’t respond when you touch it, often a strip along one edge or a patch where the screen was cracked or pressed. In the grid test, squares in a dead zone stay dark however often you swipe over them, and show up red when you finish.
What are ghost touches?
Ghost touches are taps the screen reports when nobody is touching it, so apps open or text appears on their own. In the drawing test, a ghost touch shows up as a circle or line where you aren’t touching. They are often caused by moisture, a dirty or badly fitted screen protector, a faulty charger or cable, or a damaged screen.
How many fingers can a touch screen detect?
Most modern phones, tablets and touch laptops track several fingers at once, and many track ten. The “Touch points reported” box shows the number your browser reports, which comes from the device or its driver. To see what your screen really does, open the multi-touch test and put down one finger at a time; the “Most touches at once” box shows the highest count it tracked.
Does it work on an iPhone, iPad, Android phone or touch laptop?
Yes. It runs in the browser on all of them, including Chrome, Safari, Edge, Firefox and Samsung Internet. Where the browser allows it, the test opens full screen. On iPhone, pages can’t go full screen, so the test fills the browser window instead; turn the phone sideways and back, or scroll the address bar away, to test as much of the screen as possible.
Can I try it without a touch screen?
Yes. You can hold down the left mouse button and drag to fill the grid, which shows how the test works. It can’t test a touch screen from another device, though: open this page on the phone, tablet or laptop you want to check.
Is anything I draw saved or uploaded?
No. The grid and drawings exist only on your screen while the test is open. Nothing is uploaded or stored, and closing the test clears it.