What this free screen test checks
- Dead and stuck pixel detection. Full-screen color swatches make dead, stuck and hot pixels stand out. Found a stuck one? Try the Stuck Pixel Fixer.
- OLED screen burn-in testing. Solid colors and 50% gray reveal burn-in ghosts and uneven wear. For gray levels and gradients, use the dedicated OLED burn-in test.
- IPS glow and backlight bleed check. The black screen shows light leaking at the edges and corners; the backlight bleed test adds near-black and blooming screens.
- Works on every screen: laptops, desktop monitors, iPhone and Android phones, tablets and TVs. No download required.
How to run a dead pixel test
- Clean the screen. Wipe it with a dry microfiber cloth. Dust and smudges are easy to mistake for dead pixels.
- Start the test. Press Start Test. The page goes fullscreen and every control fades away after a couple of seconds so nothing covers your pixels.
- Cycle through the colors. Click, tap, swipe or press → / Space to step through black, white, red, green, blue, 50% gray and more. Look at the whole panel from a normal distance, then up close.
- Note anything that doesn't match. A dot that stays black on white is a dead pixel. A dot that stays red, green, blue or white on black is a stuck or hot pixel.
- Try stuck pixel repair. Press R during the test to open the Stuck Pixel Fixer, tap the spot and let it flash for 10–20 minutes.
How to check a laptop screen for dead pixels
Checking dead pixels on a laptop works the same way, but a few laptop habits can hide defects or fake them:
- Plug in the charger. Many laptops dim the screen on battery, which makes dark or dim pixels harder to spot.
- Turn off auto-brightness and night light (or True Tone on a MacBook) so the colors stay pure and even.
- Check right up to the edges, including the strip near the hinge and under the webcam, where defects often hide behind a thin bezel.
- Look for keyboard marks. Faint rectangles visible on white or gray are often pressure marks from the keys, not dead pixels.
- Test a new laptop straight away. Most sellers only accept returns for dead pixels within a short window, so run a dead pixel detect pass on day one.
Dead spot or dark spot on your screen
A dead spot is a patch larger than a single pixel that stays dark, dim or discolored on every color. A dead pixel line is a thin vertical or horizontal line of pixels that is always black or always lit. Both usually come from a fault in the panel's ribbon cable or driver electronics, or from pressure damage, rather than from individual dead pixels, so software can't fix them.
Check that the spot or line stays in exactly the same place on every test color, then contact the manufacturer or a repair shop, ideally while the display is still under warranty or within its return window.
Is the speck tiny, dark and has it moved? It may be an insect trapped inside the panel. See bug inside your screen.
What the screen uniformity checker reveals
Dead pixels
Pixels that never light up. They show as black dots on the white, red, green and blue screens.
Stuck & hot pixels
Sub-pixels frozen on. A single red, green, blue or white dot stands out most on the black screen.
Backlight bleed
Light leaking in at the edges or corners of an LCD. Check the black screen in a dark room at medium brightness.
Uniformity & clouding
Patchy brightness, tinted areas, vignetting or “dirty screen effect”. The 50% gray screen shows these best.
Stuck pixel test & repair
Start with a stuck pixel test: open the black screen and look for a single dot that stays lit in red, green, blue or white, then confirm it on the other solid colors. A stuck pixel still receives power; one or more of its sub-pixels is simply frozen. Rapidly cycling colors over it can sometimes nudge it back into working order. The Stuck Pixel Fixer lets you tap the defect to drop a small box of fast-changing red, green and blue noise right on it, then move, resize, speed up or slow it down.
It's worth running for 10–30 minutes. Results aren't guaranteed, and truly dead pixels can't be revived by software, but the method costs nothing and won't harm a healthy display.
Photosensitivity warning: the Stuck Pixel Fixer flashes rapidly. Don't use it if you're sensitive to flashing lights, and look away while it runs.
IPS glow inspector: glow vs. backlight bleed
IPS glow is a silvery or amber sheen, usually in the corners, and it's a normal trait of IPS panels. Backlight bleed is light escaping through gaps in the panel assembly, and that's a defect. To tell them apart, open the black screen in a dim room and move your head: IPS glow shifts or fades as your viewing angle changes, while backlight bleed stays in the same place and shape.
For a dedicated dark-room check with near-black and blooming screens, use the backlight bleed test. OLED screens have neither problem, because each pixel makes its own light; check them with the OLED burn-in test instead.
Frequently asked questions
How do I run a dead pixel test?
Clean your screen, press Start Test and step through the fullscreen colors with a click, tap, swipe or the arrow keys. Check each color from a normal distance and up close. A dot that stays dark on bright colors is a dead pixel; a colored or white dot on black is a stuck pixel.
What is the difference between a dead pixel and a stuck pixel?
A dead pixel gets no power and stays black on every color. A stuck pixel has one or more sub-pixels frozen on, so it shows as a bright red, green, blue or white dot. Stuck pixels can sometimes be repaired; dead pixels usually cannot.
Is a bad pixel test the same as a dead pixel test?
Yes. Bad pixel is a catch-all term for any faulty pixel: a dead pixel that stays black, a stuck pixel frozen on one color, or a hot pixel that stays white. A bad pixel test uses the same full-screen colors to reveal all three, so this dead pixel test works as a bad pixel test too.
How do I detect dead pixels on a laptop screen?
Plug in the charger, turn off auto-brightness and night light, then run the fullscreen test and step through every color. Check right up to the edges, including near the hinge and webcam. A dot that stays dark on white, red, green or blue is a dead pixel; faint rectangles on gray are usually keyboard pressure marks instead.
Can stuck pixel repair really fix my screen?
Sometimes. Flashing rapid colors over a stuck pixel with the Stuck Pixel Fixer for 10 to 30 minutes fixes some stuck sub-pixels, especially recent ones. It will not revive a dead pixel. If the defect remains and your display is under warranty, contact the manufacturer or seller.
Is the Stuck Pixel Fixer safe to use?
It will not harm a healthy display. Because it flashes very quickly, do not use it if you are sensitive to flashing lights, and look away while it runs. On OLED screens, keep sessions short and avoid leaving any static image on screen for hours.
How can I tell IPS glow from backlight bleed?
Show the black screen in a dim room and move your head. IPS glow shifts or fades as your viewing angle changes and is normal for IPS panels. Backlight bleed stays fixed at the edges or corners regardless of angle and is a panel defect.
What does a screen uniformity checker show?
Solid 50% gray, white and black screens reveal uneven brightness, tinted areas, dark corners, clouding and the dirty screen effect. Turn off night light, adaptive brightness and HDR first so the display shows the colors as intended.
Does this dead pixel test work on phones, tablets, TVs and OLED screens?
Yes. It runs in any modern browser on Windows, macOS, Linux, Android, iOS and smart TVs, and supports mouse, keyboard and touch. On iPhone the browser toolbar may stay visible because iOS limits fullscreen for web pages.
How many dead pixels are acceptable?
It depends on the manufacturer. Many follow the pixel fault classes in ISO 9241-307, which allow a small number of defects per million pixels, while some brands offer zero bright dot guarantees. Test new screens within the return window and check the warranty policy.
How accurate are the display details?
Resolution, device pixel ratio and color depth come straight from your browser. Refresh rate is estimated by timing animation frames, so battery saver modes, variable refresh rate or a busy computer can make it read lower than the panel maximum.
Is any data collected?
The screen tests run entirely in your browser, with no accounts and nothing uploaded. Only if you accept analytics cookies, Google Analytics measures visits and shares standard usage data such as pages viewed, device type and screen size with Google. You can change your choice at any time with Cookie settings at the bottom of the page. The site may also show ads from Google, which use cookies; the Privacy Policy explains how to opt out of personalized ads. Your custom color and stuck pixel fixer settings are saved only in your own browser.