Testers
Dead Pixel Test
Cycle full-screen colours to find dead or stuck pixels on any monitor, laptop screen or phone display, with no app install required.
Dead pixel test
Read every check below before you go full screen: once the screen is one flat colour there is nothing else on it, so the way out has to be something you already know.
- Once you’re in, tap or click the colour to move to the next one, or use the left/right arrow keys.
- To leave, press Escape, or tap “Exit full screen”— a small button that stays at the top-centre of the screen the whole time, out of the way of the corners you’re checking.
- This browser won’t hand a web page full control of the screen, so use the maximize (⤢) control above this tool instead — the address bar will still show along one edge, but everything else fills the screen.
Jump to a colour
Read the two paragraphs below before you tap "Enter full screen" — once the screen is a single flat colour there's nothing else on it, so knowing how to get back out has to happen first. Press Escape at any time, or tap the small "Exit full screen" button that stays at the top of the screen throughout — it's positioned at the top-centre rather than a corner deliberately, so it never sits over the exact edges you're trying to inspect. Tap or click anywhere else on the colour to move to the next one, or use the left/right arrow keys if you have a keyboard attached.
Dead pixel vs. stuck pixel: what you're actually looking for
These are two different faults and this tool is built to help you tell them apart, because they're handled differently once you've found one.
A dead pixel has no power reaching it, so it never lights up at all. Look for it against the bright colours — white, cyan, magenta, yellow — where a dead pixel shows as a small black or very dark speck sitting on top of the colour, completely unaffected by what's playing on screen. It stays in exactly the same spot at exactly the same size no matter which colour is showing, which is the giveaway that separates it from dust or a scratch on the glass in front of the actual panel.
A stuck pixel is the opposite kind of fault: instead of doing nothing, it's frozen showing a specific colour — commonly red, green or blue — regardless of what the rest of the screen is doing. Look for it against black, where any stuck colour stands out clearly, and also against whichever of this tool's swatches doesn't match the stuck colour. A stuck pixel is a transistor delivering the wrong signal rather than none at all, which is why it's the one of the two that sometimes recovers — on its own over time, or with the massage-then-rapid-colour-cycling approach some people report success with (screen off, very light pressure directly on the spot, screen back on, straight into a fast colour cycle like this one). A genuinely dead pixel does not respond to any of that, because there's no signal reaching it to "unstick".
Why full screen, and why the exit has to be obvious
A dead or stuck pixel is just as likely to sit at the very edge of a panel as in the middle — arguably more likely, since edges and corners are where a panel's manufacturing and assembly tolerances are tightest. The browser's own chrome (address bar, tabs, bookmarks) occupies exactly that space in a normal window, which is why this tool asks for full screen rather than trying to do the whole job in the small preview above: full screen is the only way a flat colour actually reaches every physical edge of your display.
That only works if getting back out is never in doubt. This tool never changes colour on a timer — every transition happens because you clicked, tapped, or pressed an arrow key — and the way out (Escape, or the exit button that stays visible the entire time) is shown to you before you ever enter full screen, not discovered by trial and error once the screen has already gone black.
Reading a result you're not sure about
If you spot a speck and you're not certain whether it's a dead pixel, a stuck pixel, dust on the glass, or a smudge, try these in order: first, gently wipe the screen with a soft, dry microfibre cloth and re-run the test — dust and fingerprints are far more common than an actual panel defect and this rules them out in seconds. Second, check whether the speck moves at all as you tilt the screen or press gently near (not on) it — a genuine pixel fault never moves, while a reflection or a mark on the glass often will. Third, note which colours the speck appears against: something visible against every single colour, including black, points to a stuck pixel showing a bright colour; something visible only against the brighter swatches and invisible against black points to a dead one. If it survives all three checks, it's a real pixel-level fault, and the FAQ above covers what your options are from there.
Questions
- What's the difference between a dead pixel and a stuck pixel?
- A dead pixel has failed completely and never lights at all, so against a bright colour like white it shows as a small black or dark speck that stays put no matter what's on screen behind it. A stuck pixel, by contrast, is frozen showing one colour — often red, green or blue — and shows up as a small coloured speck against anything that isn't that colour, including black. The distinction matters because the two have different prognoses: a stuck pixel is a transistor delivering the wrong signal and sometimes recovers, either on its own or with gentle massage/pressure techniques and rapid colour-cycling software; a dead pixel has no power reaching it at all and essentially never comes back on its own. If gently massaging the area with the screen off, then cycling colours quickly, changes anything, you were looking at a stuck pixel — a dead one won't respond to any of that.
- Can a dead pixel be fixed?
- Usually no. A dead pixel means the subpixel transistor isn't receiving power, and there's no software trick that restores power to hardware — cycling colours (what this tool does) can only reveal a dead pixel, not repair one. Some people report luck with very light, careful pressure directly on the dead pixel with the screen off, then turning it back on, but this is inconsistent, can make things worse if you press too hard, and works (when it works at all) mainly on stuck pixels rather than genuinely dead ones. If a laptop or monitor is still under warranty, most manufacturers have a dead-pixel policy — usually a minimum count before they'll replace the panel — so it's worth checking that before trying anything physical.
- How many dead pixels is normal on a new monitor or laptop?
- More than most people expect. Panel manufacturers grade displays against published dead-pixel tolerance classes (ISO 9241-307 is the common standard), and a handful of manufacturers explicitly allow one, two or more defective subpixels on a brand-new panel before it counts as faulty under warranty — a single full dead pixel is usually three defective subpixels in the same spot. That's exactly why running a test like this one within the return window matters: catching it on day one, while a return or exchange is still straightforward, is a much easier path than trying to get a panel swapped six months later.
- Why does the test need full screen — can't I just look at the small preview?
- The browser's own chrome — the address bar, the tab strip, any bookmarks bar — sits right at the top and sides of the window, exactly where the small preview swatch does not reach. Panel defects cluster disproportionately near the physical edges and corners of a screen (a manufacturing and assembly-tolerance effect), so a test that can't fill those edges is blind to the area most likely to have a problem. Full screen removes the browser's own UI so the flat colour genuinely reaches every edge, which is the only way to check the corners at all.
- My screen is fine in every colour except one — what does that tell me?
- A defect that only shows up against one or two of the colours here (rather than all of them) usually means a single stuck subpixel rather than a fully dead pixel — a normal pixel is made of a red, green and blue subpixel together, and a fault in just one of them only stands out against colours where that particular channel would otherwise be off or dim. That is what the pure red, green and blue screens are for: on the red screen only the red subpixels are lit, so a dark speck there tells you the red subpixel of that pixel is the one at fault. Work through all three and you can name the channel rather than just the pixel. The cyan, magenta and yellow screens light exactly two channels each, which is how you separate a single failed subpixel from a pixel that has died completely.