Test a touchscreen in under a minute, whether it is a used phone you are about to buy, a tablet that has started ignoring taps in one corner, or a touch laptop you are not sure is sending real touch input. Paint mode turns the screen into a grid that fills in wherever you touch, so dead zones show up as dark cells. Multi-touch mode counts how many fingers the screen tracks at once, and Ghost touch watch logs any touches the screen reports while nobody is touching it.
Everything runs locally in your browser with standard Pointer Events. There is nothing to install and no data leaves the page. For the display itself, the screen test checks for dead and stuck pixels. The keyboard test checks every key on a laptop, and the webcam test checks the camera above the screen.
Frequently asked questions
How do I find dead zones on my touchscreen?
Use Paint mode. The screen becomes a grid, and every cell your finger passes over turns green. Drag slowly in overlapping rows from top to bottom, then do the same in columns, so every part of the glass is covered. A cell that stays dark after you have clearly dragged across it is a dead zone. Dead zones usually come as a strip or patch, often along an edge or where the screen was cracked or pressed, rather than a single random cell. Switch to the fine grid to pin down the exact size and shape of a patch once the coarse grid has shown you where it is. When you exit, the coverage map and the per-area counts show where the untouched cells were.
What is a ghost touch and how does this test detect it?
A ghost touch (or phantom touch) is when the screen reports a tap or swipe that nobody made — apps open on their own, the keyboard types random letters, or the screen scrolls by itself. Common causes are a damaged or poorly fitted digitizer, moisture, a cheap charger adding electrical noise, or a screen protector trapping dirt. Ghost touch watch gives you a one-second grace period, then records every touch the screen reports over the next 10 seconds while you keep your hands off. Any recorded event is a ghost, logged with its time and position, and shown as a red dot. Try it again with the charger unplugged: if the ghosts stop, the charger is the likely cause.
How many touch points does my screen support?
Open Multi-touch mode and put fingers down one at a time. Each contact gets a numbered circle, and the tool records the most it saw at once. Many phones, tablets, and touch laptops track 10 points, while others report 5 or fewer, and older hardware can stop at 2. Keep in mind that the operating system may take over certain gestures, such as a three-finger or five-finger swipe on iPad, or three-finger screenshots on some Android phones, before the browser sees them. If the count stalls earlier than expected, try placing fingers without moving them. A mouse or trackpad always reports a single pointer.
Why can’t I paint the very edges of the screen?
Phones and tablets reserve the outer edges for system gestures: swiping in from the side goes back, and swiping up from the bottom goes home. The browser never sees those touches, so edge cells may stay dark even on a perfect screen. Start each stroke a little inside the screen and drag outward toward the edge instead of starting at the edge. On iPhone the browser also cannot enter true fullscreen, so the test covers the page area and not the status bar. Rotating the device rebuilds the grid for the new orientation, so pick an orientation before you start painting. If an edge strip stays dark on a phone even when you drag outward into it, it is worth a second look.
Does this work with a mouse, stylus, or touch laptop?
Yes. The test uses Pointer Events, so a mouse, trackpad, pen, or finger all paint the grid, and the on-screen label shows which input type the browser reported (touch, pen, or mouse). That makes it easy to tell whether a touch laptop is really sending touch input or treating your finger as a mouse. Pen hover does not count as a touch in any mode: only contact with the screen is recorded. Everything runs locally in your browser, and nothing about your touches is sent anywhere or stored after you close the page.