Works with fingers on any touchscreen; on a PC you can also test with the mouse held down. Drag through every cell – edges and corners included.
Quick answer: Tap Start touch test and drag your finger across the whole screen – every grid cell you touch turns green. Cells that refuse to fill are dead zones. The counter shows how many fingers register at once, and marks appearing where you didn't touch reveal ghost touch.
Touch faults come in three flavours: dead zones (strips or patches that ignore your finger – common after screen replacements and drops), ghost touch (the screen registers taps by itself, often from a failing digitizer or cheap charger), and lost multi-touch (fewer simultaneous fingers than the panel should support). This test makes all three visible on one fullscreen grid.
It's the single most important check when buying a used phone: a screen can look flawless and still have a dead strip exactly where the keyboard's E and R keys sit. Drag slowly through every cell including edges and corners – with a clean, dry screen and no screen protector bubbles – and you'll know the digitizer's true condition in about thirty seconds.
How to test a touch screen
- Tap Start touch test – the screen fills with a grid.
- Drag your finger slowly across every part of the screen; touched cells turn green and your path draws as a line.
- Cover edges and corners – that's where replacement digitizers most often fail.
- Place several fingers at once to check the multi-touch counter (most phones support 10).
- Lift your hands completely: if new marks appear on their own, that's ghost touch. Tap Exit or press Esc to finish.
Why use the GadgetsFocus touch screen test?
- Fullscreen grid where every touched cell fills green – untouched cells expose dead zones at a glance.
- Live and maximum simultaneous-touch counters to verify multi-touch (typically 10 points on phones).
- Draw trails show exactly where the screen tracked your finger – jitter or broken lines indicate digitizer trouble.
- Coverage percentage tells you when you've tested the entire panel.
- Works on phones, tablets, touchscreen laptops and 2-in-1s – no app install.
Honest limitations
- The OS reserves some gestures (edge swipes for back/home, pull-down bars) – marks near the very edge may trigger navigation instead; test edges with slow drags rather than swipes.
- A cracked screen protector or trapped moisture causes false dead zones – remove/clean before condemning the digitizer.
- Maximum touch points are capped by the hardware and OS (often 10 on phones, sometimes fewer on laptops) – a lower number isn't a fault if it matches the device's spec.
- Ghost touch that only happens while charging points to the charger or cable, not the screen – retest unplugged.
Frequently asked questions
How do I know if my screen has a dead zone?
Drag your finger slowly through every grid cell. A genuine dead zone stays uncolored no matter how many passes you make, and the drawn trail visibly breaks as your finger crosses it. Retest after cleaning the screen and removing any protector to rule out surface issues.
What causes ghost touch?
Most often a failing or poorly fitted digitizer (especially after a cheap screen replacement), a damaged charging cable/charger injecting noise, moisture, or a bent frame pressing on the panel. If ghost touches appear here with clean, dry hands off the screen – and persist when unplugged – the hardware needs attention.
How many fingers should my phone detect?
Nearly all modern phones and tablets support 10 simultaneous touch points; some budget models and laptop touchscreens support 5. Place fingers one by one and watch the max counter – compare it with your device's spec sheet.
Why do the edges seem unresponsive?
Phone software deliberately ignores light resting touches near edges (palm rejection) and reserves swipe gestures. Slow deliberate drags should still fill edge cells. A whole edge strip that never registers even with slow drags is a real digitizer fault – common on replaced screens.
Does this test work with a stylus or gloves?
A capacitive stylus works like a finger. Standard gloves block capacitive touch entirely – that's physics, not a fault – unless the device has a dedicated glove mode or you use touch-capable gloves.
Related tools: Dead pixel test · CPS click test · Refresh rate test · Keyboard tester
Last updated: July 11, 2026. Built and tested by the GadgetsFocus team on Chrome, Edge, Firefox and Safari (desktop & mobile). Everything on this page runs locally in your browser — we never see, store or transmit your files.