Dead pixel test
Nine exact full-screen colour fields, in the order that makes each kind of pixel fault easiest to see.
Esc to exit, arrow keys to change field, H hides the controls
Auto-advance
5.0 s / field
The screen is kept awake while auto-advance runs, where your browser supports it.
Shortcuts
- ←→
- Previous / next field
- Space
- Start or stop auto-advance
- H
- Hide the controls
- Esc
- Leave full screen
What you are looking for
- Dead Black on every field, including white. A failed transistor, and not fixable.
- Stuck A coloured dot on black. Sometimes freed by rapid colour cycling.
- Dust Moves or vanishes when you wipe. The most common false alarm there is.
How to run this test
- Wipe the screen with a dry microfibre cloth first, so a speck of dust does not send you back to the shop.
- Pick a field from the list, or leave it on white to start. The nine fields cover every single-element failure between them.
- Press Click to enter full screen, then move through the fields with the arrow keys, or set an auto-advance speed and let it run.
- On each field, sweep your eyes across the screen in horizontal bands at roughly arm length. Do not try to take the whole panel in at once.
- A dot that stays in exactly the same place on every field is a pixel. A mark that moves or vanishes when you wipe is dirt.
- If you find a stuck pixel, try the stuck pixel fixer before contacting the retailer.
What a problem looks like
- Dead pixel
- Permanently off. It shows as a black dot on every field, including white, and stays black no matter what is displayed. Caused by a failed transistor and not fixable by software. This is the one worth returning a display over.
- Stuck pixel
- One or more sub-pixels permanently on, so the pixel shows a fixed colour. It appears as a coloured dot against black and disappears on the field matching its colour. Stuck pixels sometimes free themselves, and rapid colour cycling sometimes helps.
- Hot pixel
- All three sub-pixels stuck on, so it shows as a bright white dot against black. Easy to spot on the black field, effectively invisible on white. Treated the same as a stuck pixel, though it responds to cycling less often.
- Dust or a surface mark
- Looks like a dead pixel until you move your head, at which point it shifts slightly against the pixel grid, or until you wipe it and it moves. Always wipe before concluding anything. This is the single most common false alarm.
- A cluster of bad pixels
- Several adjacent faults together. Clusters are far more noticeable in use than a single dot and are treated more seriously by most manufacturer policies than the same number of scattered pixels.
What to do next
If something looks wrong, check it again in a normally lit room and from straight on, then check whether it appears on a second device. If it only happens on this screen and you are still inside the return window, that is the time to contact the retailer.
Questions people actually ask
Can this website detect dead pixels automatically?
No, and neither can any other. A web page has no way to read the light your panel is emitting, because no browser API exposes it. What this tool does is give you exact, clean, full-screen fields, which is the condition you need in order to see a bad pixel yourself.
What is the difference between a dead pixel and a stuck pixel?
A dead pixel is permanently off and shows as a black dot on a white field. A stuck pixel has one or more sub-pixels permanently on and shows as a coloured dot on a black field. Stuck pixels can sometimes be freed with rapid colour cycling; dead pixels cannot be fixed by software.
Why does the test offer nine fields?
Because different faults hide on different fields. A dead pixel hides on black, a stuck red sub-pixel hides on red, and a stuck blue sub-pixel is nearly invisible everywhere except yellow. White, black, the three primaries, the three secondaries and a mid grey cover every single-element failure.
How many dead pixels do I need before I can return a monitor?
It depends entirely on the manufacturer, the model tier and where you bought it, and the thresholds change often enough that quoting a number here would mislead you. Check the manufacturer policy page for your exact model, and check the retailer return window separately, the retailer window is often the easier route.
My new phone has one bright dot. Is that normal?
It is not unusual, and it is also not something you have to accept. Panels ship with a permitted number of defective pixels, but a visible dot on a new device is worth raising with the retailer while you are still inside the return window, which is usually more generous than the manufacturer warranty threshold.