Touch Screen Tester
Validate your Android digitizer: track every simultaneous touch pointer, find ghost inputs, and sweep for dead zones across the full screen area.
- Runs locally
- Tracks every finger
- Works offline
Touch test
About this tool
Touch Screen Tester uses Pointer Events to track every active touch, mouse, or stylus contact simultaneously. Multitouch mode draws a colored circle at each pointer position with a faint trail, and shows the current and peak simultaneous touch count for the session. Coverage mode divides the board into a grid and highlights every cell you visit, so an unvisited cell after a full-screen drag indicates a possible dead zone.
Everything runs locally in your browser. No data leaves your device.
How to use
- Multitouch: tap and hold multiple fingers at once on the board. Each finger shows as a uniquely colored circle. The stats row shows active and maximum pointer counts.
- Coverage: switch to Coverage mode, then drag one or more fingers across the entire board. Green cells are visited; gray cells are not. A persistent gray area suggests a dead zone.
- Reset: clears the board and resets coverage or max-pointer counts for the current mode.
Tips
- Remove your screen protector if you suspect a dead zone introduced by a cracked or mis-applied protector.
- Ghost touches (circles appearing with no finger) point to a hardware or water-damage issue in the digitizer.
- Test multitouch with 5 and then 10 fingers to find your device's simultaneous touch limit.
- For coverage sweeps, use the flat pad of your finger and drag slowly in overlapping rows to ensure full contact area coverage.
- Reboot your phone between tests if you see erratic behaviour. Some ghost-touch bugs are transient software glitches.
About the Touch Screen Tester
Modern Android phones use capacitive digitizers that detect the electrical change from your finger's contact with the glass. When a digitizer works correctly, it reports every touch point accurately and immediately. Problems such as ghost touches, stuck pointers, or unresponsive zones are often the first sign of physical damage, moisture ingress, or a failing display assembly. This tool gives you a fast, browser-based way to check for all of those issues.
Multitouch and pointer tracking
Android assigns each new contact a unique pointer ID. This tool mirrors that system: each pointer gets a distinct color and is labeled with its ID and type (Touch, Mouse, or Pen). If a circle appears without you touching the screen, that is a ghost event. If the circle disappears when you add a third or fourth finger, the digitizer has reached its simultaneous touch limit or has a hardware fault near that region.
Coverage and dead zones
Dead zones are regions of the screen where the digitizer reports no contact even when you press firmly. They are most common along the edges, in the corners, and near physical damage such as a crack or a screen replacement that was not bonded correctly. Coverage mode divides the board into a grid of roughly 40 px cells. Drag your finger slowly across every part of the board in horizontal and vertical passes. Any cell that remains gray after a thorough sweep is a candidate dead zone worth investigating further.
Frequently asked questions
Why does my phone show more than 10 touch points?
Most Android digitizers support 5 to 10 simultaneous pointers. Some high-end devices support more. Seeing more than the documented limit is unlikely; if you do, it may be a firmware quirk or the OS is coalescing and re-reporting older events. The max shown by this tool is the highest count seen in a single animation frame.
Can ghost touch be fixed with software?
Occasionally. If ghost touches appear only after a system update, a factory reset or update rollback may help. Persistent ghost touches that occur across reboots and recovery mode are almost always a hardware issue: a cracked digitizer, moisture under the glass, or a loose connector. A screen replacement is usually required.
Does a screen protector cause dead zones?
A thick or cracked tempered-glass protector can reduce touch sensitivity, especially toward the edges where it may lift slightly. If you suspect this, try testing with the protector removed. A thin PET film is less likely to cause sensitivity issues than a thick glass protector.
How is this tool different from the Screen Tester?
The Screen Tester focuses on pixel defects: dead pixels, stuck pixels, and burn-in. It fills the canvas with solid colors for visual inspection. Touch Screen Tester focuses on digitizer behaviour: how many contacts are tracked, where they land, and which regions of the screen respond to input. The two tools complement each other for a full display health check.
