Dead Pixel Test
Run a free dead pixel test on any phone, tablet, laptop or monitor. The tool fills your whole screen with ten solid colours and a fine grid, one at a time, so a faulty pixel has nowhere to hide. You mark anything that looks wrong and get a plain-language read-out of what it probably is.
What Is a Dead Pixel Test?
A dead pixel test fills your entire display with one solid colour at a time so that a faulty pixel becomes visible against a background it cannot blend into. A dead pixel shows as a black dot on white. A stuck pixel shows as a bright dot on black. Your own eye is the detector.
This dead pixel test runs ten full-screen patterns: black, white, red, green, blue, cyan, magenta, yellow, mid-grey, and a fine line grid. The three secondary colours matter more than most guides admit — cyan, magenta and yellow each light a pair of sub-pixels, and a partly failed sub-pixel sometimes only shows up on a combination after looking perfectly fine on the pure primary.
Everything runs inside your browser. No image is captured, nothing is uploaded, and the tool works offline once the page has loaded.
Dead Pixel vs Stuck Pixel vs Dust
People call every spot on a screen a dead pixel, but the three causes need three different responses.
| What you see | Most likely cause | Can it be fixed? |
|---|---|---|
| Black dot on a white screen, invisible on black | Dead pixel — receives no power | No. The driving transistor has failed. |
| Bright or coloured dot on a black screen | Stuck pixel — frozen on | Sometimes. Rapid colour cycling occasionally frees it. |
| Spot visible on every single colour | Dust or debris on the glass | Yes. Clean the screen and re-run the test. |
| Patches or a faint ghost image on grey | Backlight bleed or OLED retention | Panel-wide wear, not a single pixel fault. |
| A line break visible only on the grid pattern | A scratch in the glass | No, but it is cosmetic, not a pixel failure. |
Why No App Can Find Dead Pixels for You
A device cannot inspect its own screen. There is no sensor pointed at the display, so the operating system only knows what it sent to the panel, never what the panel actually lit up. When a pixel dies, the software has no idea — it keeps sending the same data and the hardware silently fails to show it.
That is why this tool never claims to have detected anything. It shows you the colours, you decide, and it records your answer. Treat any product that offers an automatic "screen health score" with suspicion, because nothing on the device is capable of producing that number.
What Warranty Usually Covers
Most manufacturers publish a dead pixel policy, and one faulty pixel is usually not enough to qualify for a replacement. Panel production has an accepted defect rate and warranties are written around it, so policies typically require a minimum count before a screen is replaced. Thresholds vary by brand and panel size, and a fault in the centre is often treated more seriously than one in a corner.
Two things help far more than arguing. Test a new device inside the return window rather than the warranty window, because a return is much easier than a claim and often closes within 14 to 30 days. And photograph the fault against both a white and a black screen with the date visible, since a dated photo is far stronger evidence than a verbal description.
Tips for an Accurate Dead Pixel Test
- Clean the screen first. A dry microfibre cloth. Dust is genuinely the most common cause of a "dead pixel" that turns out to be nothing.
- Go to maximum brightness and switch off auto-brightness, night mode, blue light filters and any colour-shifting setting. Each can hide a real fault or invent a fake one.
- Scan the corners and edges, especially around a notch or camera cutout, where faults tend to cluster.
- Look hardest at green. Human vision is most sensitive to green and green sub-pixels carry the largest share of perceived brightness, so a green fault is the most noticeable in daily use.
- Check at normal viewing distance first. A pixel you can only find with your nose against the glass is real, but it is very unlikely to meet a warranty threshold.
Last updated: 8 August 2026.
Frequently Asked Questions
What is the difference between a dead pixel and a stuck pixel?
A dead pixel receives no power and is always black, so it is visible on a white screen and invisible on a black one. A stuck pixel is frozen switched on and glows red, green, blue or white, so it stands out against black. Dead pixels cannot be revived; stuck pixels sometimes can.
Can a dead pixel be fixed?
No. The transistor driving that pixel has failed and there is nothing to restore, so no app, video or pressure trick will bring it back. A stuck pixel is different — rapid colour cycling for 10 to 30 minutes occasionally frees one, though it fails more often than it works.
Is pressing on a stuck pixel safe?
It is risky. Pressing the spot through a soft cloth on a switched-off screen does sometimes work, but on a modern bonded OLED panel it can also spread the fault or crack the digitiser. The upside is one pixel and the downside is the whole display, so we do not recommend it.
Does this dead pixel test send my screen data anywhere?
No. The tool only paints colours on your own display. Nothing is captured, no screenshot is taken, and no data leaves your browser. Once the page has loaded it works with no network connection at all.
Will one dead pixel be covered by warranty?
Usually not. Panel manufacturing has an accepted defect rate and most policies require a minimum number of faulty pixels before a screen qualifies for replacement. The threshold varies by brand, panel size and sometimes where the fault sits. Testing inside the return window is a much easier path than a warranty claim.
Why does the test include cyan, magenta and yellow?
Each of those lights a pair of sub-pixels rather than one. A partly failed sub-pixel can look fine on a pure red, green or blue screen and only reveal itself on a combination, so the three extra colours catch faults the classic six-colour set misses.
What is the grid pattern for?
Scratches, not pixels. A fine scratch in the glass is nearly invisible on a solid colour fill but shows clearly as a break in a regular thin-line grid. It is a different fault with a different repair, and worth separating from a pixel problem before you book anything.