Dead Pixel & Screen Uniformity Test
Fill your whole screen with one solid color to spot dead pixels (always off), stuck pixels (always on) and uneven color or brightness right after you buy a monitor or phone, or when you receive a used one. To compare the resolution with the spec sheet, use the Viewport Checker.
🔒 Runs in your browser · Your data is never sent to a server
Once started, click or tap (or press → / Space) for the next color, ← for the previous one, and Esc to exit. You can also pick a color below to start from it.
Start from a color
Click / → next color ← previous Esc exit
How to use
- Raise the screen brightness if you can, and wipe off any dust or smudges.
- Press "Start fullscreen test" (or a color button to start from that color) and the screen fills with one color.
- Switch colors with a click or the arrow keys, and look for dots of a different color or patches of uneven color or brightness.
- Press Esc to exit.
Notes
- White makes dark dots (dead pixels) easy to see, and black makes bright dots (stuck pixels) easy to see. Red, green and blue reveal pixels where only one color is stuck on or off.
- Dust, smudges and scratches can look like dead pixels. Wipe the screen with a soft cloth and check whether the spot is still there.
- Whether dead pixels qualify for a warranty or exchange depends on the manufacturer or store policy (number and location). Test soon after purchase and check the seller’s terms.
- Showing the same image for a long time can cause burn-in. Exit once you have finished checking.
- Browser zoom or display scaling can stop the color from covering the full screen. Where fullscreen is not supported, the test covers the whole browser window instead.
Glossary
Dead / stuck pixel
A pixel on an LCD or OLED panel that does not display correctly. A stuck pixel is always lit, a dead pixel is always dark, and some pixels show only one wrong color.
Uneven color / backlight bleed
When a screen showing one solid color looks different in color or brightness from place to place. It can come from how the backlight is mounted or from aging.
Burn-in
A faint ghost of an image left on the screen after it was displayed for a long time. OLED screens are especially prone to it.
FAQ
Which colors should I use to find dead pixels?
White makes dark dots (dead pixels) easy to spot, and black makes bright dots (stuck pixels) easy to spot. Red, green and blue in turn also reveal subpixels that are stuck on or off for just one color.
I see a dot, but is it really a dead pixel?
Dust, smudges and air bubbles under a screen protector can look like dead pixels. Wipe the screen with a soft cloth, and check whether the dot stays in the same place when you switch colors. If it does, it is probably a faulty pixel.
Can I get a replacement if my screen has a dead pixel?
It depends on the product. Many manufacturers set limits on how many dead pixels, and where on the screen, are acceptable, so a few may not qualify. Test soon after purchase and read the manufacturer or store policy.
Does this work on phones and tablets?
Yes. Open the page, press "Start fullscreen test", and tap the screen to change colors. In browsers that do not support fullscreen, the test covers the whole browser window instead.
Share this page