Dead Pixel Test for Phones and iPhone

Run the test on the phone you mean to check

1. Make the picture honest. Raise the brightness. On an iPhone or iPad, turn off True Tone and Night Shift. On Android, turn off the night light, eye-comfort or extra-dim filter, whatever the phone calls it.
2. Open the test and step through the colours. Press Start test. Move through red, green, blue, white, black and grey. If the browser cannot cover the whole display, rotate to landscape or hide the browser bars. The page says so when that happens.
3. Use white for dark dots and black for bright dots. A dead pixel is a sharp dark dot on white. A stuck or hot pixel is a coloured or bright dot on black. Wipe the glass first so you are not inspecting dust.
4. Stop if the fault is spreading or the phone is swelling. New dots, a blotch that grows, or a chassis that is lifting are hardware damage. A swelling battery can press on the display. Stop charging, do not puncture the phone, and take it to a repairer. The fixer will not reverse that.
5. Try the fixer only for a stuck LCD pixel. Most recent phones and iPads are OLED. Flashing does not repair a dead or stuck OLED subpixel, and it can stress the panel. Use the fixer only when you have confirmed a stuck pixel on an LCD, after the epilepsy warning, and only for a short time.

The browser asks for fullscreen when you press Start test. Phones often refuse. iOS Safari in particular may leave the clock, the toolbar or the home indicator on screen. The colour still covers the page, and a note asks you to rotate the device or hide the bars. Landscape shows more of the panel. Adding the page to the home screen drops some of the browser chrome the next time you open it.

On the test, tap to move forward. Esc is not on a phone. The Close control stays available. Do not leave one solid colour up for many minutes on an OLED. A static field can leave temporary image retention that looks like a stain and usually fades. That stain is not a dead pixel.

What a black screen is, and is not

People search for an iPhone black screen test for two different problems. The black colour here is a page you can see. Close is still on it. Use it in a dim room to find a hot pixel (a bright dot) or a stuck pixel (a red, green or blue dot). A dead pixel will not show on black. Check white for that.

A phone that stays black, with no picture at all, is not a single dead pixel. The panel, the battery or the software is not drawing this page, so the test cannot start. Charge the phone. Then use the restart steps on the maker’s own support page, not a button combination copied from a different model. For an iPhone, start at Apple’s iPhone support. For an iPad, start at Apple’s iPad support. Android makers each publish their own steps.

OLED, stuck pixels, and a fault that spreads

On OLED, black pixels are off. A dead subpixel is an element that will not light, so it is obvious on white and invisible on black. A stuck bright subpixel on OLED is usually an electrical fault. There is no liquid crystal to unstick. The stuck-pixel fixer is the wrong tool, and rapid flashing can stress the panel. Read the dead versus stuck page if you are not sure which fault you have. If the phone might be OLED, skip the fixer.

A single dead pixel stays one dot. Dead pixels on a phone that are spreading, a black blotch that grows, or new dots appearing over hours are a damaged panel or something pressing on it from behind. The fixer will not stop that. Back up the phone if it will still turn on.

A swelling battery is a safety problem. If the chassis is bulging or the screen is lifting, stop charging. Do not bend, press or puncture the phone. Heat and a puncture are how a damaged cell gets worse. Take it to a repairer or the maker.

An LCD iPad is the case where a confirmed stuck pixel can be tried with the fixer. Confirm the pattern first: coloured on black, gone on its own colour. Read the epilepsy warning. Nothing flashes until you press “I understand, start”. If the device asks for reduced motion, confirm again. Keep the run short. Stop is on screen the whole time. Do not press on the glass. If you do not know whether that iPad is LCD or OLED, do not start the fixer.

Repair routes

Phone makers often look at the panel rather than publishing a monitor-style class table. This site does not invent an Apple or Samsung allowance, and it does not quote a repair price.

• iPhone and iPad: start with the seller if you are inside their return window, or with Apple Support for iPhone and Apple Support for iPad.
• Android, including Samsung: the support site for the company named on the phone, in the country where you bought it, or the shop you paid.

Photograph the dot on the colour where it shows, straight on, before you book anything. The warranty guide covers what to write down, and the UK statutory rights that sit beside a manufacturer policy. A laptop screen is a different article. The colour rules match. The cable and the hinge do not.

Common questions