Dead Pixel Test
Find and document dead or stuck pixels in about a minute. The page fills your screen with black, white, red, green, blue and grey, one at a time; you look for dots that don't match. Mark anything you see, re-check it on every colour, and get a plain report with the maker's published pixel policy. Works on monitors, laptops, TVs and phones, full screen on iPhone too. Nothing is uploaded. There is no automatic scan: a web page cannot see your pixels.
Before you start: wipe the screen (dust looks exactly like a bad pixel), turn off Night Light, True Tone and auto-brightness, and sit at your normal distance.
Black → white → red → green → blue → grey → black, about 70 seconds. Pause, step back and forth, or press M to mark a spot. Esc leaves at any time.
When you leave the video, the page shows the same colour so you can mark what you saw. The Dynamic Island or notch has no pixels and iOS keeps a thin black band around it, so no app can test that area.
Chrome and Edge can tell the page the monitor's name from its driver, only if you allow it. It cannot read a serial number or warranty status.
About this dead pixel test
How to use it
- Clean the screen, turn off Night Light, True Tone, HDR and auto-brightness, and set the browser zoom to 100%.
- Press Start. The page goes full screen and shows black for 15 seconds, then white, red, green and blue, then 50% grey and black again. Look over the whole screen, corners included.
- See a dot? Press M (or Mark), tap exactly where it is, and say whether it was bright or dark and what colour. Resume when done.
- After the pass, each spot is re-checked on black, white, red, green and blue. Answer yes or no for each, and the page says what the dot most likely is.
- Pick the maker to see its published pixel policy with dates and a link, then copy the report or save the PNG card for the store or a warranty claim.
Why several colours
- Black shows bright dots: a subpixel or a whole pixel stuck on. A white dot is a whole pixel; a red, green or blue dot is one subpixel.
- White shows dead pixels (whole pixel off) and dust. A dead blue subpixel is only about 7% darker on white, so white alone misses it.
- Red, green and blue each show a dead subpixel of that colour as a black dot, and tell you which channel failed.
- 50% grey shows tint, patches and ghost images (OLED image retention or burn-in).
- Black again, while you move your head: glow that moves with you is normal IPS glow; glow that stays put is backlight bleed. Judge bleed in a lit room at 30–50% brightness, the way makers do.
Dead, stuck, bright, dark: which is it?
Makers disagree on "stuck" and "dead", so warranties mostly count bright dots (always on) and dark dots (always off), each either a whole pixel or a single subpixel. This page uses those words and treats stuck, hot and dead as aliases. Dust and marks smaller than half a subpixel are excluded by most policies.
How many dead pixels are acceptable?
It depends on the maker and the product line, not on a universal rule. Dell UltraSharp, HP Z, ASUS ProArt and some others allow no bright dots at all; most mainstream lines allow 2 bright and 5 dark subpixels; MSI needs more than 3 bright or 5 dark; ViewSonic counts whole pixels; Samsung US, Apple and Microsoft publish no number. The result card shows the row for your maker with its page date.
Can a website fix a stuck pixel?
Not credibly. Flashing "fixers" have no published evidence, Dell advises against software fixers and pressing on the panel, a full-screen flash breaks accessibility guidance on seizures, and fixing a bright dot can throw away a zero-bright-dot replacement. This page has no fixer. Try the return window or the maker's policy instead.
Dead pixel test on iPhone
iPhone doesn't let web pages go full screen, so this page plays short self-hosted colour clips in Apple's video player, shaped to fill the screen to the corners on every iPhone. Its controls fade after a moment. When you leave the video, the page shows the same colour so you can mark what you saw. No app can test the Dynamic Island or notch area.
What a browser cannot test
A web page chooses the colour value it asks for; your browser, operating system (Night Light, HDR, True Tone), monitor settings and panel decide what light comes out. It cannot see pixels, measure brightness, colour accuracy or refresh rate, read your monitor's serial number, or check a warranty. The "frame rate drawn" figure is how fast the browser drew frames, not your refresh rate. On a phone, the model is not identified.
Privacy
The test runs entirely in your browser and this page loads no analytics at all. Monitor detection happens only when you press the button and allow it, and stays on your device. Saved marks live in your browser's storage until you forget them. Reports and cards are files created on your device and only go where you send them.