Buying a new monitor, TV, laptop or phone, or checking a second-hand one? Fill the screen with pure red, green, blue, white, black and more to spot dead and stuck pixels, use gradients to find banding, and fine patterns to check sharpness. The tool also shows your screen size, pixel ratio and measures the refresh rate.
loading toolHow to test a screen for dead pixels
- Clean the screen and turn brightness up.
- Press Start full-screen test; tap or press → to move through the colours, Esc to exit.
- Look for dots that do not match the colour around them.
Good to know
- Check returns policies: many shops allow a return for dead pixels within a short time.
- Measure the refresh rate with this tab in front and without scrolling.
Questions
What is the difference between a dead and a stuck pixel?
A dead pixel never lights, so it shows as a black dot on every colour. A stuck pixel stays one colour (often red, green or blue) and is easiest to see on black.
Why does the refresh rate show 60 Hz on my 144 Hz screen?
Browsers follow the rate your system is set to. Check Display settings → Advanced display → refresh rate, and use a cable that supports high refresh rates.
Is my data private?
Yes. Everything happens inside your own browser: nothing you type or choose is uploaded to us or anyone else.
Is it free?
Completely free, with no sign-up, no watermark and no limit on how many times you use it. Light ads keep the site running.
