Monitor & Dead Pixel Test
One colour at a time, the whole screen, nothing else on it.
This is for looking at a screen. It cannot repair a pixel, and the flashing patch may help some stuck pixels at best — no promises.
- Reported size
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- Pixel ratio
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- Refresh rate (estimate)
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Dust and marks on the glass look like stuck pixels. Wipe the screen and check again.
Whether a panel qualifies for replacement is the manufacturer’s own policy, not this page.
Everything happens on this device.
How to use
- Press start. The screen fills with one colour and the controls get out of the way.
- Click, tap, press → or space for the next screen; ← goes back and Esc leaves.
- Look for dots that stay dark or stay coloured, for light leaking at the corners, and for bands in the gradient.
Examples
A dot that will not go away
Step through white, red, green and blue. A dot that is black on every one of them is dead; one that stays the same colour on all of them is stuck.
Light leaking at the edges
The black screen in a dark room shows backlight bleed and clouding at the corners, which a bright desktop hides completely.
Steps in a gradient
The black-to-white ramp shows banding; the grey and grid screens show whether the brightness is even across the panel.
The colour you picked
To read a colour off a picture rather than fill the screen with one, that is the other tool. Image Color Picker
FAQ
Dead vs stuck pixels?
A dead pixel looks black on every colour because it is off. A stuck pixel stays lit in one colour — red, green or blue — whatever the screen shows.
Can it fix pixels?
No. Some people report that a flashing patch has helped a stuck pixel; the effect is not guaranteed and it does not apply to dead pixels at all.
Is the flashing safe?
The flashing only starts after you confirm a warning, and it is limited to three flashes a second. If you are photosensitive, do not use it.