Dead Pixel & Screen Test
Fill your screen with solid colours to spot dead pixels, stuck pixels, backlight bleed and colour problems on any monitor, laptop or phone.
The test goes fullscreen. Click or press → to change colour, and Esc to exit.
How to Use This Test
- Clean your screen with a microfiber cloth first — fingerprints and dust look exactly like dead pixels and will waste your inspection time.
- Click Start screen test to enter fullscreen mode.
- Click anywhere or press the right arrow key to cycle through test colours: red, green, blue, white, black, and grey.
- On each colour, scan slowly from corner to corner. Look for any dot that doesn't match the solid background colour.
- On the black screen, dim your room lights and look for bright patches near the edges — this reveals backlight bleed.
- Press Esc to exit fullscreen when done.
What Your Results Mean
A dot that stays black on every colour: Dead pixel — it receives no electrical signal. Dead pixels almost never recover on their own.
A dot that stays one fixed colour regardless of background: Stuck pixel — powered on but locked to one sub-pixel colour (usually red, green, or blue). Stuck pixels can sometimes be recovered.
A dot that's wrong on some colours but not others: Partial stuck pixel — one of the three sub-pixels is misbehaving while the others work.
Bright patches near the edges on the black test: Backlight bleed. A small amount at the corners is normal for IPS panels. Bright bands along the edges that are visible during normal use is above acceptable levels.
Faint grey clouds on the black test: Clouding — uneven backlight distribution. Common on edge-lit panels, and it often worsens with age.
Faint lines across the display: Can indicate failing display circuitry or cable issues on older monitors.
Common Problems and Fixes
Found a stuck pixel. Can it be fixed?
Sometimes. Rapidly cycling colours over the affected area for 10–30 minutes can free a stuck sub-pixel. Gently massaging the exact location through a soft cloth while a flashing pattern runs occasionally helps. Don't apply firm pressure to an LCD panel. This doesn't always work, but it's worth trying before making a warranty claim.
Found a dead pixel. What are my options?
Check your manufacturer's dead pixel warranty policy before assuming nothing can be done. Most makers set a minimum count before they'll replace a panel, but some premium lines have zero-tolerance policies. Act within your return window — most retailers give 14 to 30 days.
Backlight bleed is visible during normal use
A small amount of edge glow in a dark room on a solid black screen is within manufacturing tolerance for IPS panels. Bleed that's visible during normal content — movies, games, or browsing — is a quality defect. Contact the retailer if the screen is new.
Can't get the test to go fullscreen
Make sure you're clicking the Start button directly rather than using a keyboard shortcut. Some browsers block fullscreen requests not triggered by a click. On iOS, full fullscreen isn't available — use a desktop browser for the most complete check.
Why This Test Matters
This test should be the first thing you do with a new monitor or laptop screen. Most retailers have a 14–30 day return window, and manufacturers have specific pixel defect policies — both are time-limited. Finding a problem on arrival gives you clear grounds for a return before that window closes.
For photographers and video editors, even a subtle defect in the centre of the screen affects colour work over hundreds of hours. Catching it early means choosing a panel that actually suits the work, not discovering the problem after the return window has closed.
Why Dead and Stuck Pixels Happen
A blemish on an otherwise clean panel almost always falls into one of a few categories, and which one it is decides whether you can do anything about it.
Manufacturing defects are the most common: a transistor that never received power leaves a pixel permanently dark from day one, which is why testing a new screen on arrival matters so much. Stuck subpixels happen when one of a pixel's red, green or blue elements jams in the on position — these can appear after months of use and are sometimes recoverable. Pressure and impact damage the liquid-crystal layer, often producing a cluster or a small bloom rather than a single dot. And heat and age gradually take a toll on any panel, which is why a faint stuck pixel can show up years in.
There's no operating-system fix for a true dead pixel — it's hardware — so the practical question is identifying which type you have and whether it crosses your manufacturer's replacement threshold.
Dead Pixel vs Stuck Pixel vs Hot Pixel
This is the distinction that determines your next move, and the colour-cycling in this test is how you tell them apart. A dead pixel stays black on every colour, including white — the subpixels get no power, and it's almost always permanent. A stuck pixel shows a fixed colour: it stays lit on some test screens and visible against others, because one subpixel is jammed on. A hot pixel is the opposite of dead — permanently white on every colour. Stuck pixels are the only group with a realistic chance of recovery, so if your dot changes appearance as you cycle through red, green, blue, white and black, that's good news.
How to Try Reviving a Stuck Pixel
- Clean the screen first. A speck of dust or a smudge mimics a stuck pixel perfectly. Wipe gently with a dry microfibre cloth before assuming the worst.
- Run rapid colour cycling. Flashing the area through colours quickly for 20–30 minutes "exercises" the subpixel and frees a meaningful share of stuck pixels. Several free pixel-fixer videos and tools do exactly this.
- Try gentle pressure. With the screen off, place a soft cloth over the spot and apply light, targeted pressure with a fingertip or a rounded stylus while turning it back on. Press lightly — too hard creates new problems.
- Combine pressure with cycling. Light pressure while the colours flash works more often than either alone.
- Know when to stop. If 30–40 minutes brings no change, it likely won't recover. Don't keep pressing harder.
- Use your warranty window. If the dot is a true dead pixel, this is the moment to check the return or warranty policy while you still can.
Frequently Asked Questions
What's the difference between a dead and a stuck pixel?
A dead pixel receives no signal and stays black on every colour. A stuck pixel is powered but locked — it shows one colour regardless of background. Stuck pixels are more common and can sometimes be fixed. Dead pixels almost never can.
Can stuck pixels fix themselves?
Occasionally, especially in the first few days. Running a colour-cycling pattern over the area gives them the best chance of recovering. The longer they stay stuck, the less likely recovery becomes.
Does this work on a phone or tablet?
Yes. Open the page on any mobile browser and run the test. Full-screen mode may be limited on some mobile browsers.
How many dead pixels is a panel allowed to have?
It depends entirely on the manufacturer's pixel policy. Some premium monitor lines have zero-tolerance. Others allow one or more depending on location. Check your specific model's documentation.
What if backlight bleed appeared after I bought the monitor?
Bleed can worsen over time. If it's within the manufacturer's warranty period and has increased noticeably, it may be covered as a defect. Contact manufacturer support.
Should I do this test on every new screen?
Yes, always. On arrival, before the return window closes. It takes two minutes and gives you the ability to act if something is wrong.
Can dead pixels be fixed?
A true dead pixel — black on every colour — almost never recovers, because the subpixels get no power. Stuck pixels, which show a fixed colour, can sometimes be revived with rapid colour cycling or gentle pressure. Clean the screen first, since dust is often mistaken for a stuck pixel.
How many dead pixels before a warranty replacement?
It varies by manufacturer and is set against industry standards, but most makers only replace a panel once it has several bright or dark dots, and the threshold is often stricter for dark dots than bright ones. Check your specific warranty policy, and if the screen is new, act within the return window where the bar is usually far lower.