Touch Screen Test

How do I test my touch screen?

Draw over the whole grid and look for places where the line breaks. These five steps take about a minute.

1. Clean the screen and dry your hands, so dirt or water does not cause false touches.
2. Press Full screen, so the test covers the whole display, edges included.
3. Drag one finger slowly across every row of the grid until the coverage reads 100%.
4. Watch for gaps in the line, or cells that will not fill. These mark a dead zone.
5. Put down more fingers at once and check the Most at once number.

Pay most attention to the edges and corners, because damage and dead zones often start there.

What faults can this test find?

It finds four common touch faults. Each one looks different on the grid:

• Dead zone: a gap in the line, or a cell that will not fill.
• Ghost touch: a dot or line you did not draw.
• Lag: the line trails well behind your finger.
• Missed multi-touch: fewer fingers counted than you put down.

How many touch points does my screen support?

The Screen reports number is the most touches your browser says the screen can track at once. Put down that many fingers and check that Most at once reaches it.

A reading of 0 means the browser found no touch screen. Most desktop monitors read 0, and so do touch screens whose driver is missing.

What causes ghost touches?

Dirt, water and a badly fitted screen protector are the usual causes. Clean and dry the screen, then run the test again without touching it.

If dots still appear on their own, unplug the charger and test once more. A screen that makes ghost touches on battery power may have a hardware fault.

What should I do if part of the screen does not respond?

Restart the device first, because a stuck driver can stop touch input. Then try these in order:

• remove the case or screen protector if it presses on the edge,
• install any system updates,
• on Windows, run Calibrate the screen for pen or touch input from the Control Panel.

If the same cells stay empty after all that, the digitizer may be damaged. Take a photo of the grid for the repair shop or the seller.

Does this work on a laptop, tablet or monitor?

Yes. It runs in any modern browser on phones, tablets, touch laptops and touch monitors. On a touch monitor, check that its USB touch cable is connected as well as the video cable.

How do I check touch on an iPhone or Android phone?

This page is the quickest check on any phone. Each system also has a built-in way to see touches:

• Android: turn on Developer options, then switch on Show taps or Pointer location.
• Samsung Galaxy: many models open a hidden test menu when you dial *#0*#.
• iPhone: there is no touch test menu, so use this page or move an app icon across the whole screen.

Turn the developer settings off again when you finish, since they draw over every app.

How do I check touch on a Windows laptop?

Open Device Manager and look under Human Interface Devices for a HID-compliant touch screen. If it is missing or shows a warning, Windows cannot see the touch layer.

Right-click it and choose Disable, then Enable, to restart it. Then run this test again in full screen.

Why does touch stop working when my hands are wet?

Most phone and laptop screens sense the small electric charge in your finger. Water also carries charge, so drops on the glass can read as extra touches or block real ones.

Dry the screen and your fingers, then test again. Normal gloves block the charge too, which is why touch screen gloves have conductive fingertips.

Should I test a new or used device before I keep it?

Yes. A used phone or laptop can look fine and still have a dead strip near the edge. Run this test before you pay, or before the return window closes.

Pair it with our dead pixel test to check the display as well as the touch layer. If you find a fault, see our dead pixel return rules for what sellers usually accept.

How do I keep a touch screen working well?

Most touch problems come from the surface, not the hardware. A few habits help:

• wipe the screen with a dry or slightly damp microfiber cloth,
• avoid strong cleaners that can strip the coating,
• replace a screen protector once it lifts, bubbles or cracks,
• keep the case edge clear of the glass.

Does a stylus test the screen the same way?

A plain rubber or mesh stylus works like a finger, so it tests the same touch layer. Its fine tip makes it easier to trace the edges and corners in a straight line.

An active pen, such as an Apple Pencil or a Surface Pen, sends its own signal to the screen. Test with your finger as well, because a pen can work while finger touch does not.

What is the difference between a dead zone and a dead pixel?

A dead zone is a part of the touch layer that does not feel your finger. A dead pixel is a dot on the display that does not light up.

They are separate faults in separate layers, so a screen can have one without the other. This page finds dead zones, and our dead pixel test finds dead pixels.

What if I need a touch screen for a desk setup?

A portable touch monitor adds a screen you can tap next to a laptop. Check our monitor dimensions pages to see how much desk space each size takes.

Can I use this test on a tablet?

Yes. It works in the browser on any iPad, Android tablet or Windows tablet. Press the full screen button, then drag across every part of the glass, including the corners.

Hold the tablet in both portrait and landscape and test again. A fault near the edge can be easier to spot when the screen is turned.