You noticed something. A tiny dark spot on your iPhone screen that wasn't there before — or maybe it glows a wrong color in a dark room. Before you drive to the Apple Store, it's worth knowing what you're dealing with: is it a dead pixel, a stuck pixel, a smudge, or something else entirely?
This guide walks you through how to run a proper dead pixel test on your iPhone, interpret what you find, and understand what Apple's warranty actually covers.
Why Safari — Not Chrome
On iOS, third-party browsers like Chrome and Firefox can't achieve true full-screen mode because Apple restricts that capability to Safari. In Chrome, the browser toolbar stays visible, covering the top 50–70 pixels of your display — exactly where defects sometimes hide.
To maximize screen coverage in Safari:
- Open deadpixelcheck.com in Safari
- Tap the AA icon in the address bar → choose Hide Toolbar
- Or use the Share button → Add to Home Screen, then open as a web app
The web app approach gives you the cleanest test experience — the screen fills edge to edge, and you can swipe between colors without any browser chrome in the way.
How to Run the Test: Step by Step
Once you have deadpixelcheck.com open full-screen on your iPhone:
- Find a dim room. Dead pixels and stuck pixels are dramatically easier to spot in low ambient light. A bright room can wash out subtle defects.
- Set brightness to maximum. Swipe down from the top-right corner to open Control Center and crank brightness to 100%.
- Run each color screen: Solid red → green → blue → white → black. Spend 10–15 seconds on each.
- Scan slowly. Move your eyes from corner to corner, edge to edge. Pay special attention to corners (where manufacturing defects cluster) and center (where stuck pixels from pressure damage are most common).
- Note the location of anything suspicious — tap the spot gently to confirm it's on the screen, not a dust particle on top of the glass.
Pro Tip
Hold the iPhone at an angle under a lamp after the test. A dead pixel shows as a flat black dot with no light refraction. A dust particle under the glass shows iridescent edges when you shift the viewing angle. This immediately distinguishes the two without needing any tool.
What You're Looking For: Dead vs. Stuck vs. Dust
Not every anomaly on your screen is a dead pixel. Understanding what each type looks like will tell you whether to worry — and how to handle it.
True Dead Pixel
A dead pixel is a pixel where the OLED sub-pixel circuitry has permanently failed. It appears as a tiny black dot that stays black on every color screen — red, white, green, all of them. It does not respond to the cycling test or any software fix. Dead pixels are hardware failures that require display replacement.
Stuck Pixel
A stuck pixel is one where the transistor is frozen — the pixel is on but can't update to the correct color. On a red screen, a stuck pixel might show blue or white. On a white screen, it might show a single solid-color dot. Stuck pixels often resolve on their own within days or respond to a rapid color-cycling video. They're not the same as dead pixels, and Apple treats them differently in warranty evaluation.
Hot Pixel
A hot pixel (also called a bright pixel) stays on even when the screen should be completely black. It's most visible on the black test screen — a white or brightly colored dot on an otherwise-black display. Hot pixels are common on OLED panels and are technically a form of stuck pixel.
Pressure Damage (Not a Pixel)
If you've dropped your iPhone or pressed hard on the screen, you might see a spreading dark blotch or a rainbow-colored pressure mark. That's not a dead pixel — it's physical damage to the LCD layers (on older iPhones) or OLED panel. These marks spread over days and require display replacement regardless of warranty status if the cause was physical damage.
Warning
A spreading dark patch or blotch that grows larger over hours is almost certainly physical LCD damage (liquid crystal leakage) or OLED panel crushing. This is not fixable by software and will continue to worsen. Book a repair appointment before the damage spreads to a larger area of the screen.
iPhone Screen Technology: OLED vs. LCD
Your iPhone's panel type determines exactly what you're testing and what kinds of failures are possible.
iPhone X and later (OLED): All modern iPhones — including the entire iPhone 16, 15, 14, 13, and 12 series — use OLED panels. OLED pixels are self-emissive: each pixel generates its own light. Dead pixels appear as black dots because the OLED element itself has burned out.
iPhone 8 and earlier (LCD): Older iPhones used LCD panels with a separate backlight. Dead pixels on LCD appear as black dots when the backlight shines through a failed liquid crystal cell. LCD screens can also develop pressure damage — those spreading dark blotches.
The important difference for testing: on OLED iPhones, a completely black dot in any non-black screen test is almost certainly a hardware dead pixel. On older LCD iPhones, there's also a chance the backlight assembly is failing rather than the pixel itself.
Apple's Warranty Coverage for Dead Pixels
Here's what Apple will and won't do — and it matters a lot depending on whether you're still in the warranty window.
Standard Limited Warranty (1 Year)
Apple's one-year limited warranty covers manufacturing defects, which includes dead pixels that appeared without physical damage. Unlike monitor manufacturers who publish a minimum defect threshold (e.g., "5 dead pixels before we replace it"), Apple evaluates iPhone claims on a case-by-case basis at the Genius Bar.
In practice: a single visible dead pixel in a prominent location — center of the screen, not hiding in a corner — is routinely replaced at no charge within the warranty period. Apple's goal is customer satisfaction, and a dead-pixel display is a visible, documentable defect.
AppleCare+ Coverage
AppleCare+ extends warranty coverage to 2 years (or 24 months of accidental damage coverage) and includes screen replacement for accidental damage at a fixed service fee. If your dead pixel is the result of a drop, standard warranty won't cover it — but AppleCare+ damage coverage will for a fee.
What to Document Before Your Appointment
- Take a close-up photo of the dead pixel on a white or single-color background
- Note when you first noticed it (spontaneous vs. after a drop)
- Screenshot the color you were looking at when you first saw it
- Run the dead pixel test and record the screen so the dot appears on multiple colors
Apple Genius Bar staff see dead pixel claims daily. Clear documentation — especially a video showing the dot persisting through multiple color screens — makes the evaluation faster and the outcome better.
Can You Fix an iPhone Dead Pixel?
The honest answer depends on whether it's truly dead or just stuck.
Stuck pixels: Sometimes fix themselves within 24–72 hours. You can try a stuck pixel cycling video — there are free ones on YouTube that flash colors rapidly and can occasionally shock a stuck pixel back to normal operation. It doesn't always work, but it takes 10 minutes and has no downside.
True dead pixels (OLED sub-pixel failure): Cannot be fixed without display replacement. The underlying organic LED element has physically degraded, and no software intervention changes that. Don't waste time on pressure fixes, pixel massage techniques, or heat treatments — these either do nothing or risk making the damage worse.
If the pixel is within Apple warranty, replacement is the right path. If it's out of warranty and you have one small dead pixel in a corner, many users simply live with it. If it's in a distracting location, third-party screen replacement runs $80–$150 depending on iPhone model and shop.
The most effective dead pixel prevention is a quality tempered glass screen protector that absorbs micro-impacts before they reach the OLED panel. A good tempered glass protector also makes the screen easier to inspect — defects stand out more clearly against a clean surface.
Browse Top-Rated Screen Protectors on Amazon →
Testing a Used or Refurbished iPhone
If you're buying a used iPhone or got a refurbished unit from a third party, the dead pixel test is the first thing you should run — before you agree to the sale price or let the return window close.
eBay and Facebook Marketplace sellers are not obligated to disclose pixel defects unless you ask specifically. Apple-certified refurbished iPhones come with a full 1-year warranty and go through display inspection — they're generally safe. Third-party "refurbished" units from Amazon Renewed, Swappa, or resellers vary widely.
The rule: if you have the phone in your hands, run the test before you commit. One minute of testing is worth far more than a weeks-long return dispute.