Dead Pixel Tester
Check your screen for dead, stuck, and hot pixels. The test fills your whole display with one solid color at a time — clean the screen first, then cycle through the colors and scan for any tiny dot that doesn't belong.
← → change color · Esc exit
Dead pixels appear as black dots that never light up.
Stuck and hot pixels glow as bright dots — also check for backlight bleed.
A stuck sub-pixel shows the wrong color against a pure field.
How it works
A healthy pixel is built from a red, a green, and a blue sub-pixel that mix to make any color. When you flood the screen with a single solid color, every pixel should show the exact same shade — so a faulty one breaks the uniform field and becomes easy to spot. A white screen drives every sub-pixel to full brightness, making a dead (black) pixel obvious; a black screen turns everything off, so a stuck or hot pixel glows against it. Cycling the pure red, green, and blue screens isolates each sub-pixel, which is how you catch one that's stuck on or refusing to light.
Dead, stuck, and hot pixels
- Dead pixel — stays black on every color because it gets no power. Best seen on a white screen, and almost always permanent.
- Stuck pixel — frozen on one color (red, green, blue, or a mix) regardless of what should be shown. Best seen against a contrasting field, and sometimes recoverable.
- Hot pixel — permanently lit white. Easiest to catch on a black screen, where it shows as a bright point.
- Backlight bleed — not a pixel fault, but the black screen also reveals uneven glow leaking from the edges of an LCD panel.
For an accurate test
- Clean the screen first — dust and fingerprints are the most common false alarms.
- Dim the room and view the panel straight on so glare and reflections don't hide a defect.
- Set your display to its native resolution so each on-screen pixel maps to one physical pixel.
- Scan slowly and methodically, then re-cycle the colors to confirm anything suspicious isn't just dirt or compression noise.
Frequently asked questions
What's the difference between a dead pixel and a stuck pixel?
A dead pixel receives no power, so it stays black on every color and never lights up — it usually points to a broken transistor and is almost always permanent. A stuck pixel still gets power but is frozen on one of its sub-pixels, so it shows a constant red, green, blue, or mixed dot that's most obvious against a contrasting background. The practical test is to cycle through solid colors: a fault that's black on white is dead, while one that stays a bright color (or stays white on a black screen, a so-called hot pixel) is stuck, and stuck pixels sometimes recover.
How do I test my screen for dead pixels?
First clean the screen with a microfiber cloth, because dust and smudges are easily mistaken for defects. Then start the full-screen test and step through each solid color — white and black are the most revealing — scanning the whole panel for any dot that doesn't match the field around it. Use a white screen to catch dead pixels (black dots), a black screen to catch stuck or hot pixels (bright dots) and backlight bleed, and the pure red, green, and blue screens to catch a single stuck sub-pixel. If you spot something, cycle back to confirm it's in the panel and not dust, glare, or video compression.
Can dead or stuck pixels be fixed?
Dead pixels are a hardware fault with no reliable software fix, so a truly dead pixel generally stays dead. Stuck pixels have a better chance: rapidly flashing colors over the spot can sometimes coax the sub-pixel back to life, and very gentle pressure on the area with a soft cloth (with the screen off, then on) helps some people, though it carries a small risk of making things worse. There are no guarantees with either method, and if a panel is under warranty it's usually safer to claim it than to experiment.
How many dead pixels are normal, and can I return a screen because of them?
A few dead or stuck pixels are common enough that most manufacturers don't consider them a defect on their own. Policies follow the ISO 9241-307 standard (formerly ISO 13406-2), which sorts panels into classes and sets thresholds for how many bright, dark, or partially faulty pixels are allowed before a screen counts as faulty. The exact limit varies by brand, panel class, and whether it's a premium or zero-bright-dot product, so check the specific warranty for your device — some retailers also offer a separate zero-dead-pixel guarantee.
Does this work on a phone, laptop, or TV?
Yes — the test is just full-screen solid colors, so it runs in any modern browser on phones, tablets, laptops, monitors, and smart TVs. On a phone, tap to change color and remember that very high pixel density makes a single dead pixel tiny, so look closely and test in a dark room. On a TV, open the page in the built-in browser or cast a browser tab, and use the remote's arrow keys to cycle colors.
I see a dark spot — is it a dead pixel or just dirt?
Wipe it first: dust, lint, and oily fingerprints are the most common false alarms and usually move or smear when you clean the screen, while a real dead pixel stays put in exactly the same place. A dead pixel is also razor-sharp and exactly one pixel wide, whereas dirt tends to be soft-edged and irregular. If the spot survives a clean and stays fixed as you cycle through every color, it's far more likely to be a genuine panel defect.