Touch Screen Test
Free touch screen test: swipe to fill the grid and find dead zones, and see every finger with a live multi-touch counter. Works on any phone, tablet, or laptop. Cells light up wherever a touch registers, so unresponsive strips and corners stay dark. Drawn trails reveal jumpy or broken tracking, and the counter shows how many fingers the screen detects at once — useful after a screen replacement or before buying a used device.
What you can use it for
- Check a phone or tablet after a screen replacement
- Find dead zones on a used device before you buy it
- Confirm how many fingers a touchscreen laptop detects at once
- Diagnose ghost touches and jumpy tracking
How to test a touch screen for dead zones
- Open the test on the phone, tablet, or touchscreen laptop and tap Fullscreen so browser bars don't hide the edges.
- Pick a grid size. Large cells are quick; small cells find narrow dead strips.
- Slowly drag one finger across every row, then every column. Cells turn green wherever a touch registers.
- Look for cells that stay dark after two or three passes and trails that break in the same place every time — that's a dead zone. A healthy screen reaches 100% coverage.
How to check multi-touch
Put two, then three, then five fingers on the screen at once and watch Max at once. Most phones and tablets detect 5–10 touches, and touchscreen laptops usually support 10. If the count drops when fingers are close together or near an edge, the digitizer is struggling.
Common touch screen problems and what they mean
- A dark strip that never fills — a damaged digitizer line, often after a drop or a low-quality screen replacement.
- Trails that jump or break at random — a loose display connector, or a screen protector with an air gap. Remove the protector and test again.
- Ghost touches (trails you didn't draw) — moisture, a noisy charger, or a failing digitizer. Unplug the charger and retest.
- Edges that won't fill — rounded corners, notches, and gesture areas block the outermost millimetres on many phones. That's normal; a dark strip away from the edge is not.
Before you buy a used phone or tablet
Run this test before you pay: a full-coverage grid in two minutes tells you more than any seller's promise. Then check the panel with the dead pixel test and confirm the display speed with the refresh rate test.
Frequently asked questions
How do I find a dead zone?+
Go fullscreen and slowly swipe across every cell. Cells you touched turn colored; any cell that stays dark after several passes is a likely dead zone.
How many touch points should my phone support?+
Most modern phones and tablets detect 5–10 simultaneous touches. Place several fingers down at once and check the Max touches counter.
Why won't the edges fill?+
Rounded corners, notches, and browser gesture areas can block touches right at the edge. If a strip stays dark away from the edges, that's more likely a real fault.
Does it work with a mouse or stylus?+
Yes. Any pointer works, so you can also test a stylus or a touchpad-driven cursor.
More screen tests
Dead Pixel Test
Cycle full-screen colors to find dead and stuck pixels fast.
Screen Uniformity Test
Check brightness and color evenness across the whole panel.
Monitor Ghosting Test
Frame-locked moving objects to spot ghosting, smearing, and overshoot.
Refresh Rate Test
Measure your real monitor Hz, frame time, jitter, and dropped frames.
Backlight Bleed Test
Pure black screen with corner markers to spot edge light leak.
Color Banding Test
Exact 8-bit gradient ramps to reveal banding, tints, and crushed shadows.
Contrast Test
Shaded squares to calibrate black levels and white clipping.
Resolution Test
Live readout of native resolution, scaling, refresh rate, HDR, and viewport.
Text Sharpness Test
Tiny text samples to judge subpixel rendering and clarity.
Overscan Test
A 1-pixel grid and corner circles to fix overscan and cropping.