How to check a monitor for dead pixels
Updated October 2026 · TapTest guides
Whether you have just unboxed a new monitor or you have spotted a tiny speck that will not wipe away, checking for dead pixels is quick and worth doing. A pixel fault is easiest to catch in the first days of ownership, when a return or warranty claim is simplest, so a five-minute test on a new screen is time well spent.
A pixel is one of the millions of tiny dots that make up your display, and each is built from a red, a green and a blue sub-pixel. When one of those stops behaving, you get a visible spot. You can hunt for these by filling the screen with solid colours in the screen tester, which makes a faulty pixel stand out against a plain background in a way normal content hides.
Dead pixel or stuck pixel?
The distinction matters because it decides whether a fix is possible:
- A dead pixel receives no power and stays black on every colour. It is the harder type to fix, because the sub-pixels are not lighting at all.
- A stuck pixel is lit but frozen on one colour, so it shows as a persistent red, green, blue or white dot. Because it is still receiving power, a stuck pixel can sometimes be coaxed back to life.
Telling them apart is the first job of the test, and the full-screen colour method does exactly that.
How to run the test
Open the screen tester and cycle through the solid full-screen colours: black, white, red, green and blue at least. Here is what each one reveals:
- On a white or light screen, look for dark or black dots, which are usually dead pixels.
- On a black screen, look for dots that stay lit, which are stuck pixels glowing when the rest of the screen is off.
- On red, green and blue screens, look for any dot that is the wrong colour, which exposes a single misbehaving sub-pixel.
Do this in a dimly lit room so faint faults are easier to see, and get close enough to inspect the whole surface, moving across it section by section. Give your eyes a moment on each colour, since a single wrong dot among millions is easy to skim past.
Clean the screen first
Before you conclude anything, make sure you are not looking at dust or a smudge. Turn the monitor off, which makes marks on the glass easier to see, and wipe gently with a dry microfibre cloth. A speck that moves or wipes away was never a pixel fault. Only a spot that stays in exactly the same place on every colour is a true pixel problem.
Trying to fix a stuck pixel
A stuck pixel is worth attempting to revive, though there is no guarantee. Two methods are commonly used:
- Rapid colour cycling. Playing fast-changing colours over the stuck pixel can sometimes jolt the sub-pixels back into action by exercising them quickly. Leaving such a pattern running over the affected area for a while is the gentlest thing to try first.
- Gentle pressure. With the screen on, place a soft cloth over the stuck pixel and apply very light pressure with a fingertip or a blunt, soft object while the area cycles through colours. Press softly and briefly, because too much pressure can create more faults, so this is a careful last resort rather than a first move.
A dead pixel, which never lights at all, rarely responds to either method, since the problem is a lack of power rather than a stuck state.
When a pixel fault is covered by warranty
Manufacturers do not treat every single faulty pixel as a defect, because perfect panels are hard to produce. Many have a policy stating how many dead or stuck pixels, and in what positions, qualify a screen for replacement, often expressed with reference to a longstanding display quality standard. A single stuck pixel may not meet the threshold on a budget monitor, while premium and professional screens sometimes promise zero bright pixels. Check your monitor's specific pixel policy, because it varies widely, and this is exactly why testing on arrival matters: a fault found in the return window is far easier to resolve than one you notice months later.
Testing a brand new monitor
Make the colour test part of your unboxing routine. Set the monitor up, run through the full-screen colours in the screen tester before you even install anything else, and inspect the whole surface. If it passes, you can relax knowing the panel is clean. If it fails, you are in the strongest possible position to return or exchange it while everything is fresh and within the return period.
Common questions
What is the difference between a dead and a stuck pixel? A dead pixel stays black because it gets no power. A stuck pixel is lit but frozen on one colour. Stuck pixels can sometimes be fixed; dead ones usually cannot.
Can I fix a dead pixel? Rarely, because it is not receiving power. The revival methods work mainly on stuck pixels, which are lit but frozen.
Is one dead pixel covered by warranty? It depends on the maker's pixel policy, which sets how many faults qualify. Some premium screens replace for a single bright pixel; many budget ones do not. Check your model's policy.
How do I know it is a pixel and not dust? A pixel fault stays in exactly the same spot on every colour and does not wipe away. Clean the screen first to rule out dust and smudges.