Dead Pixel Test

Test a monitor, laptop, or phone screen for dead and stuck pixels. Fill the whole display with pure white, black, red, green, blue, and the in-between colors, then look for any dot that's the wrong color or stays black. A dead pixel stays dark on every color, a stuck pixel shows one color and won't change. Handy when buying a used screen or checking a new one before the return window closes. Everything runs in your browser, nothing is uploaded.

Tech

Pick a color to fill your whole screen, then look closely for any dot that's the wrong color or stays black. A dead pixel stays black on every color. A stuck pixel shows one color (red, green, or blue) and won't change. Cycle through all the colors to catch both. Click anywhere or use the arrow keys to move between colors, and press Esc to exit.

For the clearest result, run this at your screen's native resolution and wipe the display first - dust and smudges look a lot like stuck pixels. A stuck pixel can sometimes be revived by gently massaging it or running a rapid color flicker over the spot. Everything happens in your browser, nothing is uploaded.

Dead vs stuck pixels

A dead pixel gets no power, so it stays black on every color you throw at it - easiest to spot on a white field. A stuck pixel is jammed showing one sub-pixel, so it glows red, green, or blue and stands out against black or the opposite color. Cycle through all the colors and watch the same spot to tell which one you've got.

How to run the test

Clean the screen first - a speck of dust looks exactly like a stuck pixel. Run the test at the screen's native resolution, click a color to fill the display, then click or use the arrow keys to step through the rest. Look across the whole panel, including the corners. Press Esc when you're done.

Trying to revive a stuck pixel

Stuck pixels sometimes come back on their own. Flickering rapid colors over the spot or very gently massaging it with a soft cloth can occasionally unstick one. Dead pixels, where the sub-pixel gets no power at all, generally can't be fixed and may be covered by the manufacturer's warranty.

Nothing leaves your device

The test is just solid colors painted by your browser. No camera, no upload, no tracking - close the tab and it's gone.