Dead Pixel Test — Check Your Screen for Stuck Pixels
A dead pixel is permanently off and shows black on every colour. A stuck pixel is permanently on in one sub-pixel and shows a fixed red, green or blue dot. You cannot reliably see either against normal content — you find them by filling the screen with one flat colour at a time, which is exactly what this page does.
What people use the dead pixel test for
Check a new monitor while it is still returnable
Manufacturers publish dead-pixel thresholds that a panel has to exceed before it counts as defective, and those thresholds are often higher than buyers expect. Test on day one, while your retailer's no-questions return window is still open.
Inspect a used or refurbished device
Run the full cycle before money changes hands. A stuck pixel is easy to miss on a busy desktop and impossible to miss on a flat field.
Distinguish dust from a defect
A speck of dust on the glass looks identical to a dead pixel until you check whether it moves when you tilt the screen or wipe it. Run the test, find the spot, then confirm with a cloth before you file a warranty claim.
Try to un-stick a stuck pixel
Stuck pixels sometimes recover from rapid colour cycling, which exercises the sub-pixel transistor. It is not guaranteed, but it costs nothing to try.
How to use the dead pixel test
- 1Clean the screen first — dust and fingerprints will masquerade as defects.
- 2Press F for fullscreen so no browser chrome hides part of the panel.
- 3Step through red, green, blue, white, black and grey using the arrow keys or the auto-cycle.
- 4Look at the whole panel on each colour, including the corners, from about arm's length.
- 5Note anything that stays the wrong colour across multiple screens — that is a real defect, not a reflection.
Frequently asked questions
What is the difference between a dead and a stuck pixel?+
A dead pixel receives no power and stays black on every colour, including white — those effectively never recover. A stuck pixel has one or more sub-pixels locked on, so it shows as a constant red, green, blue, cyan, magenta, yellow or white dot, and it sometimes can be recovered.
Can I fix a stuck pixel?+
Sometimes. Rapidly cycling colours over the area for 10–30 minutes can free a stuck transistor. Very gentle pressure with a soft cloth over the pixel while the screen cycles is the other common method — gentle being the operative word, since too much pressure creates permanent damage. Dead pixels do not respond to either.
How many dead pixels before a warranty claim?+
It depends entirely on the manufacturer and the panel class. Many consumer policies tolerate several sub-pixel defects before replacing a panel, while zero-bright-dot warranties on professional monitors cover a single one. Check your specific model's policy — and check within the retailer's return window, which is usually more generous than the manufacturer's.
Do I need to install anything?+
No. Everything on whitescreen.studio runs inside the browser tab you already have open. There is nothing to download, no extension and no account.
Is it free?+
Yes, all of it, with no sign-up and no usage limit.