Sweep your finger across a coverage grid and add several fingers at once. GearCheck Lab records only browser-reported touch contacts, highlights covered regions and shows the highest simultaneous touch count observed during this session.
LOCAL INPUTTouch coordinates and coverage remain in this browser session.
Touch-only diagnostic
Coverage grid & multi-touch visualizer
WAITING FOR TOUCH
Use the touchscreen itselfDrag one finger across the whole grid in overlapping strokes. Then add more fingers to test simultaneous contacts.
How to run a complete touchscreen test
Open this page on the phone, tablet or touchscreen laptop you need to check.
Clean and dry the screen. If a protector or case is implicated, compare results with it removed when practical.
Enter fullscreen and choose Coverage.
Drag one finger slowly across the grid in overlapping horizontal passes, then repeat with vertical passes.
Trace every edge and corner deliberately. Repeat any blank or interrupted region three times at a slower speed.
Choose Multi-touch, place two fingers in the area and add contacts one at a time without sliding them off-screen.
Compare ACTIVE TOUCHES with MAX SIMULTANEOUS OBSERVED; treat BROWSER MAX TOUCH POINTS as capability context, not a promised result.
Reset and repeat in another orientation. If a fault follows the same physical screen area, restart the device and compare in another app or browser.
What the live counters mean
Grid coverage is the share of cells that received at least one browser touch sample.
Active touches is the number of contacts currently reported inside the test area.
Max simultaneous observed is the highest contact count reached during this page session.
Browser max touch points comes from navigator.maxTouchPoints; it describes exposed capability, not a measured hardware limit.
Touch samples counts processed touch samples, including coalesced Pointer Events when the browser provides them.
An untouched blank cell is not a failure. A useful warning is a gap or dropout you can reproduce deliberately in the same physical region.
Interpret the result without overclaiming
Label
What you observed
What to do next
PASS
Slow overlapping sweeps cover the intended grid regions, drag paths stay continuous and the contact count remains stable for the number of fingers used.
The browser reported the deliberate inputs in this session. This does not certify the digitizer or rule out an intermittent or app-specific fault.
WARNING
A gap, edge miss, drag interruption or lower-than-expected contact count appears, but it is not yet repeatable across attempts.
Clean and dry the screen, remove a suspect protector or case, slow the sweep, change orientation and repeat in another browser or app.
FAIL
The same physical strip or region repeatedly ignores deliberate touch while neighboring areas work, and the pattern survives a restart and comparison outside this page.
Back up important data and consult the device maker or a qualified repair service. This page supplies supporting evidence; it cannot diagnose the damaged component.
Troubleshoot by symptom
A repeatable dead strip or island
Mark the area with slow passes from several directions. If the same physical region stays blank after a restart and in another app, capture a screenshot of the grid and seek device-specific support.
Only the edges fail
Enter fullscreen and repeat. System navigation gestures, browser chrome, a tight case lip or a poorly fitted protector can make an edge difficult to reach.
A drag breaks and resumes
Slow down and keep one consistent finger angle. Moisture, palm rejection, browser gesture handling and intermittent contact can all interrupt a path.
Fewer simultaneous touches than expected
Keep every finger inside the stage and add them separately. Compare another app before assuming the hardware limit is lower than advertised.
Browser and hardware limitations
The page reads browser Pointer Events whose pointerType is touch; mouse and pen events are excluded.
It cannot read raw digitizer electrodes, pressure thresholds, firmware logs or touch behavior at the lock screen.
Operating-system gestures can reserve edges even in fullscreen.
Grid resolution and browser sampling can hide very small or very brief faults.
A screen protector, case, moisture, gloves, charging interference or an app-specific gesture layer can change behavior.
Use the dedicated Ghost Touch Test for contacts that appear while your hands are off the screen. That symptom needs a hands-off monitoring workflow rather than deliberate coverage sweeps.
Touch screen test FAQ
Can a browser test prove the digitizer is broken?
No. This page shows whether browser touch events reach regions of the test area. A repeatable gap is useful evidence, but hardware service is only a reasonable next step after you reproduce the same physical gap across a restart and another app or browser.
Why are some grid cells still blank?
A blank cell can mean your finger never crossed it, moved between sampled events or passed through an area reserved for a system gesture. Sweep the spot slowly several times before treating it as suspicious.
Why can I not reach the very top or bottom edge?
Browser and operating-system controls can reserve edge gestures. Fullscreen reduces browser chrome, but a webpage cannot take control of every physical-screen edge.
Does 100% coverage prove the touchscreen is perfect?
No. It means every grid region reported at least one touch in this session. Intermittent dropouts, pressure-dependent faults and behavior limited to another app may not appear.
Why is the observed touch count below the browser maximum?
The browser maximum is capability information from navigator.maxTouchPoints, not a guaranteed result. The observed count depends on how many contacts the current device, operating system and browser expose at the same time.
Is touch data uploaded?
No. The diagnostic processes touch coordinates in the page and keeps the coverage result in the current browser session.
Related diagnostics and review policy
Continue with a focused check, or review how GearCheck Lab qualifies browser-based evidence and handles local input.
