Check If Your Screen Has Dead Pixels
A dead pixel is a dot on your screen that no longer lights up, leaving a permanent dark mark on the image. Click any colour below to open our dead pixel test. It will fill your whole screen with it so that you can perform a dead pixel check on your device. Look for spots that do not match. A dead pixel will always be black, while a stuck pixel will be lit to any of these colors — and probably fixable. Our dead pixel test is free, runs in your browser, and takes about a minute.
Dead pixel test for monitors and laptops
Run a free dead pixel test on any computer monitor, laptop or external display. The test fills your screen with solid red, green, blue, white and black, so a dead or stuck pixel stands out immediately against the flat colour.
- Clean your screen so dust and smudges are not mistaken for a dead pixel.
- Pick a colour above. It opens full screen; the arrow keys or a click cycle through the rest.
- Check every corner for a dot that stays black, white or one single colour.
Dead pixel test for smartphones and tablets
Mobile browsers cannot fill the screen with a flat colour, so we test iPhone, Android and iPad screens with full-screen video instead. Play it at the highest quality available, in landscape, and watch for pixels that never change.
- 16:9 — most phones, laptops and monitors
- 16:10 — MacBook, WUXGA and WQXGA screens
- 21:9 — ultrawide monitors
- 4:3 — iPad and QXGA tablets
Dead Pixel Fixer: repair stuck pixels
A stuck pixel is frozen on one colour rather than switched off, and it can often be revived. Our free dead pixel fixer flashes red, green and blue over the affected area at high speed to work the sub-pixels loose. Drag the flashing square onto the faulty spot and leave it running for at least an hour, with your screen saver and auto-lock switched off.
A genuinely dead pixel receives no power at all and rarely comes back, but the fixer costs nothing to try and is worth running before you start a warranty claim. On a phone or tablet, use the dead pixel fix videos instead.
Not sure which one you have? Read what to do about a dead pixel on your screen, or every method for reviving a stuck pixel.
Open the Dead Pixel Fixer
What is a pixel?
All screens are made of a large number of dots that turn on or off and can show a particular colour. Simply put, these dots are pixels. This macro shot of a computer screen shows the individual pixels that make up the image. Each pixel is made of three sub-pixels showing red, green and blue at varying intensity.
If you want the full picture, we explain how LCD screens work in detail.
What is a dead pixel?
Sometimes pixels malfunction. A dead pixel receives no power and never lights up, leaving a permanent black dot on your monitor or phone screen. It looks like the black dot in this image.
Wondering where they come from? See what causes dead pixels.
Dead pixels and stuck pixels are not the same thing
There is a real difference between dead pixels and stuck pixels. A stuck pixel is frozen on one colour because one or more of its sub-pixels is blocked on. It may look perfectly normal in some images and appear as an odd bright dot in others: if the green sub-pixel is stuck at 100%, a white screen looks fine but a black screen shows a green dot.
The distinction matters, because you have a far better chance of reviving a stuck pixel than a dead one.
How common are dead pixels on your brand?
We keep dead pixel statistics from the tests run on this site, broken down by screen manufacturer. Pick yours to see what proportion of displays came back clean.
Dead pixel guides
What is a dead pixel?
A dead pixel is a single dot on your screen that receives no power and never lights up, so it stays black whatever image is behind it. This guide explains how the fault happens at sub-pixel level, and how to tell a genuine dead pixel from a speck of dust, a smudge or a dark spot in the panel coating.
Read the guideWhat is a stuck pixel?
A stuck pixel still receives power but is frozen on red, green or blue, so it shows as a bright coloured dot against dark scenes. This guide covers why sub-pixels lock in the on position, how to spot one during a dead pixel test, and why stuck pixels are the ones you have a realistic chance of repairing.
Read the guideDead pixel or stuck pixel?
Dead pixels and stuck pixels look alike at a glance but have different causes and very different odds of a fix. This guide walks through a two-minute check — cycling black, white, red, green and blue — that tells the two apart, and explains what each result means for a repair or a warranty claim.
Read the guideWhat causes dead pixels?
Most dead pixels are manufacturing defects that were present the day the panel left the factory, but pressure on the screen, heat, humidity and simple age all add more over time. This guide explains each cause in turn, and the habits that keep a monitor, laptop or phone display clean for longer.
Read the guideHow to test a screen for dead pixels
The full method for monitors, laptops, phones and tablets: what to clean first, which colours to run, how close to sit and how long to look at each one. This guide also lists the mistakes that hide real faults — a dirty screen, a compressed video, a display running scaled rather than at native resolution.
Read the guideHow to clean a computer screen safely
Dust and grease are mistaken for dead pixels far more often than any real defect, so rule them out before you go looking for one. This guide covers which cloth and which liquid are safe on a matte or glossy panel, how much pressure is too much, and why household glass cleaner ruins an anti-glare coating.
Read the guide
Other screen tests
DeadPixelTest.org and its affiliate sites offer other ways to check that your monitor, laptop or TV is behaving.
Frame Rate and Motion Blur Test
FrameRateTest.org measures your monitor's refresh rate — how many frames per second it actually draws. A 120Hz or 144Hz panel makes motion look smoother for gaming and video. The same test measures motion blur, the smearing behind moving objects.
Test your frame rate
Backlight Bleed Test
BacklightBleedTest.org checks an LCD or LED screen for backlight bleed and IPS glow, where light leaks around the edges of the panel and shows as bright patches on dark scenes.
Check for backlight bleedScreen Resolution Test
Our screen resolution test reports the real pixel dimensions of your display — 1920x1080, 2560x1440, 3840x2160 — plus pixel ratio and colour depth, so you can confirm a monitor is running natively rather than scaled.
Test your screen resolutionScreen Contrast Test
Our screen contrast test shows how well your display separates black from white using greyscale gradients, so you can calibrate brightness and contrast without crushing shadow or highlight detail.
Test your screen contrast