Fill your screen with black, white, red, green, blue and grey to spot dead and stuck pixels. No flashing.
Fill the screen with one solid colour at a time and look for any dot that does not match. A dead pixel stays dark and shows up on white. A stuck pixel stays lit in one colour and shows up on black, or on a colour that does not contain it, such as a green dot on a red screen. The page offers black, white, red, green, blue and grey. Press Start full screen test, then click, or press an arrow key or Space, to move through them. Press Esc to leave. Go through all six: a defect in one colour channel can be invisible on the other screens.
White shows dead pixels, because a pixel that is off is a dark dot on a bright field. Black shows pixels that stay on, which are bright dots. Red, green and blue each light only one third of every pixel, so a sub-pixel that is stuck or dead in that colour stands out on its own screen. Grey is the one for uneven brightness, faint stains, dust and marks under the surface. Look from close up, a hand's width from the glass, and move your head a little: dust can be wiped off, a pixel cannot. Clean the screen with a dry microfibre cloth first, because dust looks like a dead pixel.
Some sites offer a pixel fixer that flashes rapidly changing colours on a spot of the screen. This page does not, on purpose. Rapid flashing can trigger seizures in people with photosensitive epilepsy, and a flashing patch could be shown to someone who does not expect it. Every screen here is a single steady colour that changes only when you click or press a key. Whether a stuck pixel can be recovered depends on the panel, and this page makes no claim that it can.
The colours are painted by your browser, so they are only as exact as the browser and the display settings. Night mode, a colour filter or a low colour profile can tint the screens and hide a fault. The test needs the browser's full screen mode, which most desktop browsers and tablets allow. iPhone browsers usually do not offer it for this, and there the Start button is disabled with a message. Esc leaves full screen. Nothing is saved or sent, and the page counts visits with Google Analytics, never anything about your screen.
A dead pixel is off and shows as a dark dot on a white screen. A stuck pixel is on all the time and shows as a coloured or white dot on a black screen. A stuck pixel is often one sub-pixel, so on the red screen it may be the only dot that is not red.
Press Start full screen test and go through black, white, red, green, blue and grey, taking your time on each. Click or press the right arrow key for the next colour and the left arrow key to go back. Press Esc to leave.
Pixel fixers flash rapidly changing colours, which can trigger seizures in people with photosensitive epilepsy. This page only shows six steady colours that change when you click or press a key, and it makes no claim that a stuck pixel can be repaired.
Browsers on iPhone usually do not let a page show an element in full screen for this. The button is disabled with a message in that case. Android browsers and tablets usually allow it. Use a laptop or desktop monitor if you cannot.
Maybe not. Dust or a mark on the glass is on top of the picture and does not change with the colour. A dot that is dark on white, or bright on black, and stays there when you clean the screen and shift your head, is a pixel fault.
No. The colours are drawn in your browser, in this tab, and nothing about your screen is uploaded or saved. The page counts visits with Google Analytics, never what you see.