# Dead Pixel Test: Find Stuck Pixels and Screen Defects

> Free full-screen dead pixel test: solid colors and gradients reveal dead, stuck and hot pixels, backlight bleed, banding and burn-in on any screen.

Canonical page: https://controllertests.com/screen-test/

Fill your display with pure colors and gradients to spot dead, stuck and hot pixels, backlight bleed and banding.

**Interactive tool:** this page hosts a free test that runs locally in the visitor's web browser (no install, no upload). To use it, open https://controllertests.com/screen-test/ in a browser on the device that has the hardware attached.

## What you are looking for

Every pixel on an LCD or OLED panel is made of red, green and blue **subpixels**. Faults show up as dots that ignore the color the screen is asked to display. Showing one solid color at a time across the whole screen makes them easy to spot.

- **Dead pixel:** stays black on every color. Most visible on the white screen.
- **Stuck pixel:** one or more subpixels stay on, so the dot shows as red, green, blue (or a mix) regardless of the background. Most visible on black and on the opposite colors.
- **Hot (bright) pixel:** stays lit white. Most visible on black.
- **Backlight bleed:** on LCDs, light leaking around the edges or corners, visible as brighter patches on the black screen in a dark room.
- **IPS glow:** a soft glow that changes with your viewing angle. Unlike bleed, it shifts or fades when you move your head.
- **Uniformity problems and banding:** blotches, darker corners or vertical bands on the gray screens, and visible steps in the gradient ramps.
- **Burn-in (image retention):** faint ghosts of static content such as taskbars or channel logos, mostly on OLED screens, best seen on 50% gray.

## How to run a dead pixel test

1. Wipe the screen with a dry microfiber cloth so dust isn't mistaken for a pixel fault.
2. Set the browser zoom to 100% and the brightness fairly high. For the black screen, dim the room.
3. Press **Start full-screen test**. Step through the colors with `Space`, the arrow keys, a click or a tap.
4. Scan the whole screen slowly, section by section, at a normal viewing distance. A phone camera zoomed in helps confirm a suspicious dot.
5. Note the position and color of any fault, then press `Esc` (or the ✕ button) to exit.

## Method and limits

The test fills the screen with exact solid colors (for example pure red is `#ff0000`) and smooth gradients using the browser's Fullscreen API, so no page elements, borders or scrollbars get in the way. On devices that don't allow a web page to go full screen — notably iPhone Safari — the test fills the browser window instead; hide the toolbars by scrolling or rotating to landscape for the best view. The cursor and the on-screen hint fade out after a few seconds so they don't cover pixels.

A web page can't detect pixel faults by itself: the screen's output never travels back to the browser, and screenshots capture the image the computer sends rather than what the panel shows. You do the inspection; the test provides the clean, uniform colors that make faults stand out. Night-light modes, True Tone, HDR and color filters can tint the colors, so turn them off while testing.

## Why there is no flashing “pixel fixer”

Some sites offer rapidly flashing colors that claim to unstick pixels. We deliberately don't: fast flashing patterns can trigger seizures in people with photosensitive epilepsy, and the evidence that flashing repairs stuck pixels is anecdotal. Dead pixels — where a subpixel no longer receives power — cannot be revived by software at all.

## Warranty and pixel policies

Manufacturers usually publish a pixel policy that defines how many bright, dark or subpixel faults must be present — and sometimes where on the screen — before a panel qualifies for repair or replacement. Many are based on the pixel fault classes of ISO 9241-307 (formerly ISO 13406-2). Policies vary by brand and product line, and some retailers accept returns for any fault within the return window, so test new screens as soon as you get them and check the exact wording for your model.

## Browser and device support

| Platform | True full screen | Notes |
| --- | --- | --- |
| Chrome, Edge, Firefox (desktop) | Yes | Esc always exits |
| Safari (macOS) | Yes | — |
| Chrome, Samsung Internet (Android) | Yes | Tap to advance |
| iPadOS Safari | Yes | Tap to advance |
| iPhone (any browser) | Window only | Rotate to landscape and scroll to hide toolbars |
| Smart TV browsers | Varies | Use the arrow keys on the remote |

## Frequently asked questions

### Can a dead or stuck pixel be fixed?

A dead pixel usually can't — the subpixel has lost power. A stuck pixel sometimes recovers on its own or after gentle pressure with a soft cloth while the screen is off, but pressing can also cause damage. If the screen is new or under warranty, check the pixel policy and contact the seller first.

### Is backlight bleed a defect?

Some edge light is normal on LCD screens, especially at high brightness in a dark room. Bright patches that are clearly visible in normal content, or that cover a large area, are worth reporting. IPS glow, which shifts with viewing angle, is a normal trait of IPS panels.

### Does this test work on phones, tablets and TVs?

Yes. Open the page in the device's browser. Phones and tablets advance with a tap; TV browsers usually work with the remote's arrow keys. On iPhone the colors fill the browser window rather than the entire screen.

### Why should the browser zoom be 100%?

The solid colors fill the screen at any zoom, but the gradients are smoothest and the on-screen controls are sized correctly at 100%. It also makes sure no scaling blurs a single faulty pixel into its neighbors when you inspect it.

### How do I check an OLED for burn-in?

Use the 50% gray and near-black screens at moderate brightness and look for faint shapes from static content such as navigation bars, logos or HUDs. Faint retention that fades after a few minutes is temporary; shapes that persist are burn-in.

## Related tests

- [Speaker & headphone test](https://controllertests.com/speaker-test/)
- [Reaction time test](https://controllertests.com/reaction-time-test/)
- [Mouse tester](https://controllertests.com/mouse-test/)
- [Keyboard tester](https://controllertests.com/keyboard-test/)
- [Controller tester](https://controllertests.com/controller-test/)

_Last updated: 2026-10-01_