How to use the Dead Pixel Test
- Clean the screen, then click Start full-screen test.
- Look closely at each solid color: a black dot on white is a dead pixel; a bright red, green or blue dot on black is a stuck pixel.
- Step through the gradient and grid patterns to check for banding, uneven brightness and backlight bleed, then press Esc.
Dead pixels vs stuck pixels
A dead pixel stays black whatever is shown — easiest to see on the white, red, green and blue screens. A stuck pixel is lit permanently in one color (often red, green or blue) and stands out on the black screen. Stuck pixels sometimes recover after hours of normal use or gentle pressure with a soft cloth while the screen is off; dead pixels rarely do.
Backlight bleed and uniformity
On the black screen in a dark room, LCD monitors may glow at the edges or corners — backlight bleed. Some glow (IPS glow) is normal and changes with viewing angle; bright patches that stay put are bleed. The grey screens reveal uniformity problems such as darker corners or a dirty-screen effect, and the gradients show banding — visible steps where a smooth ramp should be.
Check before the return window closes
Most manufacturers accept a few dead pixels under their pixel policy (ISO 9241-307 classes), so test a new monitor, laptop or TV right away and keep a photo of any defect. The refresh-rate estimate helps confirm that a 120 Hz or 144 Hz display is really running at its full rate — if it shows 60 Hz, change it in your system display settings.
Tools that pair well with the Dead Pixel Test
- Webcam Test — Check that your camera works and looks good before a video call — see the live picture, the real resolution and frame rate, and save a snapshot.
- Keyboard Tester — Press every key and watch it light up on the on-screen keyboard — find dead, stuck or repeating keys, see the key and code for each press, and check how many keys register at once.
- Click Speed Test (CPS) — How fast can you click?
- What Is My Screen Resolution — Your screen and browser window sizes in CSS pixels, the device pixel ratio and the real physical resolution — measured live by your browser.