How to run a dead pixel test
Clean the screen first with a dry microfibre cloth, turn the brightness up, and dim the room — a speck of dust in a bright room is the single most common false positive. Then start the full-screen test and step through each colour, scanning the whole panel including the corners and the very edges.
- Press Start full-screen test and allow full screen.
- On black, look for dots that glow. On white, look for dots that stay dark.
- Step through red, green and blue — these isolate the three subpixels inside each pixel, so a dot that fails on green only has one dead subpixel.
- Finish on grey, which is where uneven backlighting, clouding and IPS glow show up most clearly.
- Press Esc when you're done.
Dead pixel vs stuck pixel: what's the difference?
A dead pixel receives no power and stays black on every colour, including a white screen. A stuck pixel is still powered but frozen on one colour, so it shows as a bright red, green, blue or white dot — most obvious against a black screen. Stuck pixels sometimes recover; dead pixels almost never do.
| Fault | How it looks | Can it be fixed? |
|---|---|---|
| Dead pixel | Always black, clearest on a white screen | No — the transistor has failed |
| Stuck pixel | Always one bright colour, clearest on black | Sometimes, on its own over days of use |
| Hot / bright pixel | Pure white dot on a black screen | Rarely |
| Dust or grease | Moves or smears when wiped, fuzzy edges | Yes — clean the screen |
| Backlight clouding | Soft grey patches on a black screen, no sharp edge | No, but it's normal in small amounts on IPS |
How many dead pixels are acceptable?
Most manufacturers will not replace a panel for one or two dead subpixels. Warranty policies are written around ISO 9241-307 pixel fault classes, and mainstream consumer displays are typically sold to Class II, which tolerates a small number of faults per million pixels. A single bright dot near the centre is treated differently from one in a corner.
The practical rule: if you find a fault on a device you have just bought, raise it immediately. A retailer's replacement window is far more generous than the manufacturer's pixel policy, and that window closes fast. This is why testing a new laptop, phone or monitor on day one matters more than knowing the exact ISO class.
Can a dead pixel be fixed?
A genuinely dead pixel cannot be repaired outside a panel replacement. A stuck pixel occasionally unsticks by itself with normal use over a few days. The flashing-colour “pixel fixer” videos and gentle-pressure tricks work rarely, and pressing on an LCD risks spreading the damage — we've deliberately left a rapid flashing mode out of this tool, because it carries a real seizure risk for photosensitive users and almost never helps.
Checking a second-hand laptop or phone
Run this test before you pay. On a used device, also check the black screen for faint retained images — on an OLED phone or laptop, a keyboard, status bar or logo still faintly visible on a solid colour is burn-in, which is permanent and gets worse. Then confirm the rest of the hardware with the touch screen test and the refresh rate test.
Shopping rather than checking? Our guides to the best gaming laptops and the best laptops for students in India note panel quality for each pick, and foldable phones deserve extra attention along the crease.
Frequently asked questions
Is this dead pixel test accurate?
Yes, because it doesn't measure anything — it simply fills your screen with pure, uncompressed colours so your own eyes can do the work. That is exactly how service centres check panels. The only accuracy risk is a dirty screen or low brightness, so fix both before you start.
Does it work on a phone or TV?
It works on anything with a browser. On a phone, rotate to landscape and disable auto-brightness first. On a TV, open the page in the built-in browser or cast the tab from a laptop — see our guide on casting a laptop to a TV.
Why does my black screen look grey and patchy?
That is backlight bleed or IPS glow, not a pixel fault. LCD panels are lit from behind, so some light always escapes where it shouldn't, and it is most visible in a dark room on a black screen. Small amounts are normal; large bright patches at the edges are a legitimate warranty complaint.
My screen has a permanent faint shadow. Is that a dead pixel?
No — that is image retention or burn-in, and it affects OLED panels rather than individual pixels. Temporary retention fades within minutes of showing other content. If a shadow survives this colour cycle, it is permanent burn-in.