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Dead Pixel Test

Press “Start full-screen test” and the screen turns one colour. Look from edge to edge for dots that glow on black or look dark on white.

Click, tap or press → for the next colour, ← for the previous one, Esc to finish. Mark a suspicious spot with a right-click or double-click (on a phone: double-tap or long-press).

Start from this colour

Before you start, wipe the screen and turn the brightness up. Spots are easier to see.

Not tested yet

    Dead pixels do not show up in screenshots. Show the colour where you marked a spot and take a photo with a camera (if you are testing a phone, use another phone or camera).

    The colours and marks run only in this page. Nothing is sent anywhere.

    How to use

    1. 1. Wipe the screen and turn up the brightnessWipe off dust and fingerprints so you do not mistake them for dead pixels. Maximum brightness makes spots easier to see.
    2. 2. Go through the colours in full screenPress “Start full-screen test” and move on with a click, tap or →. Besides black and white, red, green, blue and other colours reveal pixels that are wrong in just one colour.
    3. 3. Mark spots and copy the resultRight-click or double-click a suspicious spot (on a phone: double-tap or long-press). When you finish, the colours and positions appear as a list and a map. Add a note such as the model and copy the result for the shop or manufacturer.

    How not to miss a spot

    • A slightly dark room makes glowing dots on black easier to see
    • First look at the whole screen from a distance, then come closer and go edge to edge
    • Corners and edges are easy to miss, so follow them as if tracing with a finger
    • On red, green and blue, look for dots that stay dark or show a different colour
    • The gray screen also makes uneven colour and burn-in easier to see

    Check new devices early

    The period for returning or exchanging a defective product is set by each shop or manufacturer. Check the screen on the day it arrives, and if something looks wrong, prepare the copied result and a photo and contact them early.

    FAQ

    Who is this for?

    Anyone who just got a monitor, laptop, phone or tablet and wants to check it while a return or warranty claim is still easy. People buying or selling used devices. Offices checking several new computers at once.

    What is a dead pixel?

    A tiny dot (pixel) on the screen that no longer lights correctly: a dot that always glows on a black screen (often called a stuck or bright pixel), a dot that stays dark on a white screen (a dead pixel), or a dot that is wrong in only red, green or blue.

    How do I tell it from dust?

    If the spot stays in the same place after wiping and appears at the same position on every colour, it may be a dead or stuck pixel. If it moves or disappears when you wipe, it is dust or dirt.

    How do I test a monitor for dead pixels?

    Wipe the screen and turn the brightness up. Press “Start full-screen test” and move through the colours with a click, tap or →. Right-click or double-click any suspicious spot to mark it, then copy the result. For an external monitor, move this browser window to it first.

    I see faint patterns or ghost images on the gray screen

    Screens that showed the same image for a long time can keep a faint trace (burn-in or image retention). It is different from a dead pixel, but if it bothers you, mark it the same way and ask the shop or manufacturer.

    What should I do if I find one?

    How many defective pixels count as a fault for an exchange or repair depends on the manufacturer, model and shop. Check the warranty and the manufacturer’s guidance, then contact the shop or manufacturer. The copied result and a photo taken with a camera make it easier to explain.

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