Find dead zones on a phone or tablet screen, count how many fingers it tracks at once, check ghost touches and measure the touch sampling rate
How to use
Open this page on the phone or tablet you want to test.
Tap Dead zone test. The screen fills with squares; slide your finger over all of them, including the edges and corners.
Squares that never light up are dead zones. Press Done to see a map of them.
Open Multi-touch and drawing to count how many fingers the screen tracks and to look for broken lines or ghost touches.
Why use this tool
Dead zone map: Every part of the screen is split into finger-sized squares. Fast swipes fill every square they cross, so a gap really means the screen missed it.
Multi-touch counter: Each finger gets its own colour and number, with the most touches tracked at once shown live.
Touch sampling rate: Slide one finger steadily to see how many times per second the screen reports it, such as 120 or 240 Hz.
Ghost touch check: Leave the drawing screen open without touching it: dots that appear on their own reveal phantom touches.
Full screen: The test hides the page and, where the browser allows, the browser bars too, so the edges can be tested.
Frequently asked questions
How do I test my touch screen for dead zones?
Run the Dead zone test and slide your finger slowly over every square. Squares that stay dark after several tries mark areas where the screen does not register touch.
What causes dead zones on a touch screen?
Cracks, a damaged digitizer, a badly fitted screen protector, moisture or a replacement screen of poor quality. Restarting the phone rules out a software glitch first.
What are ghost touches?
Touches the phone registers when nobody is touching it, making apps open or type on their own. Common causes are a damaged screen, water, a faulty charger or a protector pressing on the glass.
How many touches can a phone screen detect?
Most phones track 5 to 10 fingers at once, and tablets often 10. The page shows the number your browser reports and the most you actually managed.
What is touch sampling rate?
How often the screen checks for your finger, in times per second. Higher rates, like 240 Hz, make games and scrolling feel more responsive. It is separate from the screen's refresh rate.