TYB

Touch Screen Checker

Use this touch screen checker on the device that is misbehaving. Map every region, draw through suspected dead zones, test several fingers together, and watch for touch events you never made.

  • Real touch separated from mouse input
  • Runs locally in your browser
  • No account, app, or uploaded traces

Online touchscreen tester

Touch events stay on this device and disappear when the page closes

Waiting for touch
Active touches
0
Maximum observed
0
Reported capacity
0
Total touch starts
0

Drag a finger through every square. Untouched cells stay outlined.

Input: Waiting · Coverage: 0%

Reported capacity comes from navigator.maxTouchPoints. Maximum observed is counted only from simultaneous touch events inside the test surface; mouse and pen input remain previews.

How to use the touch screen checker

Begin with Coverage while holding the device as you normally do. Move slowly enough to hit every square, including the corners beside a case lip. Then repeat the same route in the opposite direction. A single missed cell can come from moving too quickly; a cluster that stays empty deserves a closer look.

  1. 1

    Open this page on the problem device

    Use the phone, tablet, Chromebook, or touch laptop whose screen you want to check. A mouse can preview the surface, but it does not count as touch.

  2. 2

    Map the full surface

    Drag one finger through the Coverage grid. Work across each row, then inspect any cell that remains untouched after a second pass.

  3. 3

    Draw through the doubtful area

    Switch to Draw and make several slow lines across the same location. Look for breaks that repeat in one physical strip or patch.

  4. 4

    Place several fingers down

    Use Multitouch and add fingers one at a time. Compare Maximum observed with the simultaneous contacts required by your game or gesture.

  5. 5

    Check accuracy and unwanted input

    Complete the nine targets, then run the hands-off ghost-touch observation. Repeat after removing accessories if the behavior changes.

Fullscreen gives the test more room. When a mobile browser cannot open an HTML element fullscreen, the tool switches to a viewport-filling overlay instead. Safari may still keep its address bar or home indicator, so rotate the device and repeat when either one covers the strip you need to check.

Screen touch testing for dead zones

A dead zone is a repeatable physical area where contact fails or breaks. Use the grid for broad coverage, then Draw slow horizontal and vertical lines through the same spot. Test with one finger first. A five-finger sweep is harder to read and can hide a narrow dropout behind overlapping traces.

Map

Cover the full grid twice.

Confirm

Draw across the same location.

Compare

Remove accessories and repeat.

A repeated gap carries more weight than one fast swipe. The page can only show touch events delivered to this browser surface.

Touchscreen test for missed taps and broken edges

Edges fail in annoying ways. A keyboard's outermost key may need two taps, or a game control near the lower-right corner may drop while the center feels fine. Complete the Accuracy targets with the same finger and normal pressure. The result is the distance between the browser's reported contact and each target center, measured in CSS pixels.

Pixel distance changes with browser zoom and screen density, so compare runs on the same device. A large miss once can be a hurried tap. Repeated misses pulling in the same direction near one bezel are more informative (a thick protector can make that edge feel strangely reluctant).

Multitouch test: detect simultaneous touch points

Reported capacity and observed fingers answer different questions. The browser may report five supported contacts before you touch the panel. Maximum observed rises only when this page receives several active touch pointers together. Add fingers one at a time, hold them for a moment, then move the group.

ResultWhat it meansCheck next
Reported 5, observed 5Five contacts reached the page togetherMove all five and watch every marker
Reported 10, observed 2Only two were tried or received so farAdd fingers slowly on a flat surface
Reported 0, touch detectedThe live event is stronger evidence for this pageRepeat in another current browser
Mouse previewNo touchscreen conclusionOpen the page on the touch device

Touch screen tester for ghost touches

Clean and dry the glass, then open Ghost touch and start the observation. Put the device down without touching the test surface. Any touch start delivered during those 15 seconds is counted. One quiet run is encouraging, although intermittent faults may need several attempts.

  • Disconnect the charger. A faulty cable, adapter, or electrical grounding problem can coincide with erratic input.
  • Remove moisture, a tight case, and a lifting or cracked protector.
  • Repeat after a restart, before opening games, keyboards, or drawing apps.
  • The browser cannot identify voltage noise, a loose connector, or physical digitizer damage.

How to test the touch screen on phones, tablets, and laptops

iPhone and iPad

Test in Safari, remove the case or protector when edges fail, and disconnect Lightning or USB-C accessories before a comparison run. Apple recommends those checks for intermittent response.

Android phones and tablets

Use Chrome or another current browser. Disable any game overlay or accessibility feature that changes touch behavior, then compare the same physical area in a system app.

Windows and Chromebook

Fold a convertible into its touch position and test without a mouse. Windows guidance starts with restart and optional updates; Google begins with cleaning, then a Chromebook hardware reset.

Display touch test results and browser limits

This tool listens for Pointer Events inside its test surface. Those events carry coordinates and an input type such as touch, pen, or mouse. It can show where the browser received contact, how many touch pointers were active, and whether a movement trail broke.

It cannot inspect the lock screen, hardware controller, palm rejection inside a drawing app, or manufacturer diagnostic data. And it does not measure display pixels. Use the dead pixel test for image defects, or the screen uniformity test for tint and brightness variation.

FAQ

Can this touch screen checker find a dead zone?
The coverage and drawing modes can reveal an area that repeatedly fails to report touch inside this browser. Repeat the same path twice, rotate the device, and compare another app before deciding that the digitizer needs service.
Why does reported capacity differ from maximum observed?
Reported capacity comes from navigator.maxTouchPoints, a browser value describing supported simultaneous contacts. Maximum observed counts the fingers this page actually received during your session. You must place several fingers down together to raise the observed number.
Does a mouse click count as touchscreen input?
No. Pointer Events can describe mouse, pen, and touch input. This tool labels mouse and pen activity as a preview and excludes it from touch totals, multitouch results, accuracy targets, and grid coverage.
Can the browser prove that my digitizer is broken?
No. It can map events delivered to this page. A browser cannot inspect controller voltages, the lock screen, firmware diagnostics, or touch behavior inside other apps. Persistent failures in the same physical area are useful evidence for the manufacturer or repair shop.
How should I test for ghost touches?
Clean and dry the screen, start the 15-second observation, then leave the device untouched. Repeat on battery power and without a case or screen protector. The tool records touch events delivered inside its test surface; it cannot know the physical cause.

Sources

Links go to official browser docs or primary references when available.