Dead Pixel Test for iPhone

Run a full-screen dead pixel test on any iPhone in Safari, see which colours expose dead, stuck, and burnt-in OLED pixels, and what Apple usually does about it.

An iPhone screen packs more than two million pixels into a few square inches, and a single failed one is small enough to miss until it sits under a white message bubble every day. This guide shows how to run a proper test on iOS, what each colour reveals on an OLED panel, and how to tell a dead pixel from a stuck one or from burn-in.

Open the dead pixel test

How to run the test on an iPhone

The dead pixel test works in Safari, Chrome, and Firefox on iOS without installing anything, but there is one iOS-specific limitation to know about. Safari on iPhone and iPad does not support the Fullscreen API for web pages (only for video), so the test cannot hide the browser bar for you. It fills the viewport instead. That is enough for the test itself, since the bar covers a small strip at the bottom of the screen, but if you want the whole panel visible:

1. Add the page to your Home Screen. Tap the Share icon in Safari, choose Add to Home Screen, and open the test from the icon it creates. It launches without Safari's toolbar, so the colour covers every pixel.
2. Or scroll to shrink the toolbar. In Safari a small upward scroll collapses the bar to a thin strip. Rotate to landscape and check the ends of the screen separately if the strip is still in the way.
3. Turn off screen adjustments. Before you start, disable True Tone, Night Shift, and Reduce White Point (Settings, Display and Brightness, and Accessibility). Set brightness manually rather than leaving Auto-Brightness on, so the panel does not dim halfway through.
4. Clean the glass. A speck of dust on a white screen looks exactly like a dead pixel. Wipe with a microfibre cloth and check again before deciding anything is wrong.

Once the test is running, tap anywhere to move to the next colour. Look at the screen from about 20 centimetres, then scan it slowly in a grid, because a single pixel at iPhone density is less than a tenth of a millimetre across. Double-tap to exit.

What each colour shows on an OLED

On an LCD every pixel sits in front of a backlight, so a pixel that has failed still has light behind it. OLED is different: each sub-pixel makes its own light, and a pixel that is off is genuinely black. That changes which colours are useful.

• White is the main dead-pixel screen. Every sub-pixel should be lit, so any black dot is a dead pixel and any coloured dot is a pixel with one dead sub-pixel (a cyan dot means the red sub-pixel is out, magenta means green is out, yellow means blue is out).
• Black finds pixels that are stuck on. On a healthy OLED the black screen is the same as the phone being off, so any point of light is a stuck sub-pixel. This is also the screen where a bright "hot" pixel stands out most.
• Red, green, and blue isolate one sub-pixel each. A dark dot on the red screen but not on green or blue tells you the red sub-pixel has failed, which is useful if you want to describe the fault precisely to a repair technician.
• Gray is for uniformity and burn-in rather than individual pixels. On a flat mid-gray, look for a faint keyboard, status bar, or app icons ghosted into the panel, and for a tint that differs between the top and bottom of the screen.

OLED iPhones also show a slight colour shift when viewed off-axis, and some models are known for a greenish or pinkish cast at very low brightness on gray. Those are panel characteristics, not defects, and they are not what this test is looking for.

Dead vs stuck vs burn-in

These three problems look different and have different outcomes, so it is worth being precise.

A dead pixel is permanently off. It shows as a black dot on every colour except black, never changes, and cannot be fixed by software or by pressing on the screen. The transistor driving it has failed.

A stuck pixel has a sub-pixel frozen in one state. Stuck on, it shows as a red, green, blue, or white dot on the black screen; stuck off, it shows as a coloured dot on white. Stuck pixels sometimes recover on LCD screens after a flashing fixer cycles the sub-pixel rapidly for 10 to 30 minutes. On OLED the success rate is lower, but the stuck pixel fixer is free to try. Do not massage the glass as some older guides suggest; iPhone panels are laminated and pressure can create new damage.

Burn-in is not a single pixel but a region. OLED sub-pixels dim as they age, and areas that showed a bright static element for hundreds of hours (the keyboard, a navigation bar, a game HUD) age faster than their surroundings and leave a faint permanent shadow. It is only visible on uniform content, which is why the gray screens matter. Image retention looks the same but fades within minutes; if the shadow is still there after ten minutes of varied content, it is burn-in. Our burn-in test guide covers this in more depth.

What Apple will usually do

Apple does not publish a numeric pixel-defect policy the way monitor manufacturers do. Its stores and authorised service providers assess screens case by case, and the outcome depends on how visible the defect is, whether the phone is inside its one-year limited warranty or covered by AppleCare+, and the judgement of the technician. Reports from owners suggest that a clearly visible dead or stuck pixel on a phone under warranty is often accepted for display replacement, while a single pixel that the technician struggles to see may be declined as within tolerance.

The one certain route is the return window. If you bought the phone new from Apple, you can return it for any reason within the return period (14 days in most countries), so test it on day one. Carriers and other retailers have their own windows and restocking rules, so check before you rely on them. Burn-in is generally treated as wear rather than a defect and is rarely covered outside of a documented known issue.

Checking a used iPhone before you buy

A screen fault is one of the few problems on a used iPhone that you can verify in under two minutes, so do it before money changes hands.

1. Open the dead pixel test in Safari on the seller's phone and go through white, black, and the three primaries.
2. Stop on the gray screens for a while and look for keyboard or status-bar ghosting. Burn-in on a used phone tells you it was used heavily at high brightness, which often means the battery has had a hard life too.
3. Check the edges on the black screen for a bright line or a corner that looks lighter, which can indicate a damaged or aftermarket panel.
4. Open Settings, General, About and confirm the display shows as a genuine Apple part on models that report it; an "Unknown Part" warning means the screen was replaced with a non-original one.
5. Run the touch screen test as well. Replacement screens that look fine can still have dead touch zones or ghost touches, and a screen fault plus a touch fault together almost always means a cheap replacement panel.

If the seller will not let you run these checks, walk away. A working display and digitizer are the minimum for any phone at any price.

Last updated 2026-09-16. Everything on this page runs in your browser. Nothing you type or upload leaves your device.