Dead Pixel Test and Checker

How to use this test

You are the instrument. The page only shows flat colour, which is the reliable way to see a pixel that does not behave like the ones around it. Look slowly. A fault is usually one sharp dot, not a smudge.

1. Clean the screen and sit square to it. Wipe the panel with a dry microfibre cloth. Sit straight in front of it so you are not looking from a sharp angle.
2. Turn off filters that change the colour. Use a normal brightness. Turn off night mode, blue-light filters and, on a phone, True Tone or Night Shift.
3. Start the test and step through the colours. Press Start test. Move through red, green, blue, white, black and your custom colour with a tap, Space, Enter or the right arrow. The left arrow goes back.
4. Look for a dot that does not match. Lean in. A sharp dot that stays put is a pixel. A soft mark that wipes away is dust or a smear on the surface.
5. Note where it is. Turn on the grid if you want a reference. Write down which colours show the fault and which colour hides it.
6. Leave the test. Press Esc or Close. On a phone, if the browser cannot go truly fullscreen, rotate the device or hide the browser bars. The page tells you when that has happened.

On a phone or tablet the browser sometimes cannot take over the whole display. The colour still covers the page, and a note on screen asks you to rotate the device or hide the address bar. The same thing happens on some TV and console browsers. Esc, or the Close control, always leaves.

The cursor hides after two seconds of stillness so it does not cover a dot you are trying to judge. Move the pointer and the controls come back. On a touch screen the Close control stays available.

Dead, stuck and hot pixels

These names get mixed up in shops and on forums. They are different faults, and only one of them is even a candidate for the fixer.

Each pixel on an LCD is a red, a green and a blue subpixel. A single stuck subpixel is about a third of a pixel wide. Phone OLED layouts are sometimes not a simple stripe, so a stuck element can look slightly uneven. It is still a fault.

Dead pixel versus stuck pixel goes through white, black, red, green, blue and grey, including dust and a hot pixel.

What each colour is for

• Red, green and blue: a subpixel stuck on that colour disappears. The other two show up.
• White: dead pixels, and dirt on the surface. Dirt usually looks softer and wipes away.
• Black: hot pixels. Dim the room. A sharp point is a pixel. A soft haze in the corners of an IPS panel, which shifts as you lean, is glow from the backlight, not a hot pixel.
• Custom: grey is a useful extra because it is none of the primaries, so every stuck colour has some contrast. Set it before you start, or change it on the custom screen.

Write down what you find

A warranty desk will ask where the dot is and on which colours it appears. The grid draws a 16-pixel lattice over the colour. It is a guide for position, not a ruler: browsers scale CSS pixels, so one square is not one physical pixel. Count squares from the left and from the top, or describe the screen as a 3 by 3 board (top left, centre, bottom right).

Example note. White screen, one dark dot, about a third of the way across and near the top. Still dark on red, green, blue and black. Does not wipe off. Likely a dead subpixel.

Photograph the panel on the colour where the fault is easiest to see, with the model number in the same shot if you can. Take the photo straight on. A speck that moves when you wipe with a clean microfibre cloth is not the panel.

Warranty and pixel policies

There is no single rule for how many faulty pixels a maker will accept. Policies differ by brand, by panel size and by the country you bought in, and they change. This page does not quote brand thresholds. A made-up number would be worse than none.

In general, written policies tend to do some of the following:

• Count dark pixels and bright pixels separately. Bright dots are often allowed in smaller numbers than dark ones, and sometimes not at all, because they show up on film and games.
• Treat a cluster of faults more strictly than the same number spread across the panel.
• Count only a central zone, and ignore or discount the outer edge.
• Refer to a fault class in the model’s specification, rather than a plain count. Some of those classes come from display standards. The class that matters is the one named for your model, not a class copied from another product.
• Apply for a shorter period than the rest of the warranty.

Read the warranty that came with the exact model, or the support page for that model number. Have the serial number, the purchase date and your notes ready. The warranty guide explains ISO 9241-307 fault classes and how to prepare a claim. It still does not invent a brand’s allowance.

If you bought in the UK, the Consumer Rights Act 2015 sits alongside any manufacturer chart. Goods have to be of satisfactory quality, and the retailer is responsible for that, not only the maker. A short-term right to reject applies for 30 days when goods are faulty. After that, the retailer can usually repair or replace first. A manufacturer policy that “allows” a bright pixel does not, by itself, cancel those rights. This is general information, not legal advice. Citizens Advice explains the practical steps for a faulty purchase.

What the stuck-pixel fixer can and cannot do

On an LCD, a stuck pixel is sometimes a liquid crystal that has jammed between positions. Cycling a small patch of the screen through red, green, blue, black and white makes that crystal change state quickly. In some cases it comes unstuck. In many cases nothing happens. There is no trustworthy published success rate, so treat this as a last try before a return, not as a repair.

A dead pixel (no light) and a hot pixel (always lit) are electrical. Flashing does not reconnect a failed element. Flashing also does nothing useful for OLED burn-in, a crack, or a pressure mark.

How to use it:

• Find the dot with the colour test first, so you know it is stuck rather than dead or hot.
• Press Stuck-pixel fixer. Read the warning. Nothing flashes until you press “I understand, start”. If the device asks for reduced motion, you have to confirm again.
• Choose 30 seconds, 1 minute, 2 minutes or 5 minutes. Drag the box onto the dot, or use the Left, Right, Up and Down buttons. Smaller and Larger change the box. Keep it small: the flash is meant to cover the fault, not the room.
• Stop is always on screen while it runs, in a bar that does not flash. It also stops when the timer ends. Leave the page, or press Esc, and it stops as well.

If the dot is unchanged after a couple of minutes, stop. Leaving it running for hours is unlikely to help, and on an OLED panel it is pointless and can stress the pixels.

Do not press, rub or use suction on the glass. Guides that tell you to massage a pixel can split the layers or crack the panel. This tool never asks you to touch the screen.

Flashing light can trigger seizures in some people, including people with no history of epilepsy. Do not start the fixer if that applies to you, or if someone who has photosensitive epilepsy can see the screen. Stop immediately if you feel unwell, dizzy or odd.

Phones, TVs and consoles

Monitors and laptops

Use the panel’s native resolution if you can, and sit square to it. Scaling can make one physical pixel look like a soft edge. Check at a normal distance, then lean in to confirm a speck is sharp. Turn the test off when you are finished. A static colour left up for a long time is unnecessary.

Fix a dead pixel on a laptop covers the fixer, what not to press, and how to tell the panel from a graphics fault. A Chromebook adds a ChromeOS full-screen step: dead pixels on a Chromebook.

Phones and tablets

Raise the brightness and turn off True Tone, Night Shift and any blue-light filter, or the white screen will not be white. Landscape shows more of the panel. Hide the browser bars if the page tells you fullscreen is unavailable. Add the page to the home screen if you want fewer bars next time.

On OLED phones, a solid colour left up for many minutes can leave temporary image retention that looks like a stain and usually fades. That is not a dead pixel. Do not use the fixer as a party trick on an OLED: rapid flashing is for a stuck LCD crystal.

The phone and iPad test covers a black screen, OLED limits, and a fault that is spreading.

Televisions

Open the page in the TV’s browser, or cast the tab from a phone. Many TV browsers will not enter true fullscreen. Use the on-screen note: hide the interface and, if you can, turn off pixel-shift, screen shift and logo-dimming while you look, then turn them back on. Those features move the picture by a few pixels and can make a dot seem to wander.

Motion smoothing does not create dead pixels, but it can make a photographed fault harder to see. Turn it off for the check. OLED burn-in, a ghost of a static logo, is a different problem. A flat colour can make old burn-in easier to see. This test does not measure it and the fixer will not remove it.

Consoles

Recent PlayStation and Xbox consoles can open a page in the built-in browser. Use the controller pad as the arrow keys and the confirm button as Enter. Some of those browsers block fullscreen. The colour still fills the page area. A Nintendo Switch browser, where you can open one at all, is a poor fit. Mirroring a phone to the TV is more reliable.

Guides

• Fix a dead pixel on a laptop
• Dead pixel versus stuck pixel
• Dead pixel test for phones and iPad
• Dead pixels on a Chromebook
• Dead pixel warranty policies

Common questions