How to use the screen test
- Turn the brightness up and, if you can, dim the lights in the room. Dark rooms make bleed and glow easier to see; bright screens make dead pixels easier to see.
- Clean the screen with a dry microfibre cloth. Dust looks a lot like a dead pixel.
- Press Start full-screen test. Tap, click or press → to move to the next screen and ← to go back.
- Look at each colour from about an arm’s length away, then up close at the edges and corners.
- Press Esc or tap Exit when you are done.
What each screen shows you
| Screen | Look for |
|---|---|
| White | Dark or black dots (dead pixels) and specks of dust under the glass. |
| Black | Bright dots that stay lit (stuck pixels), and light leaking in from the edges (backlight bleed). |
| Red, green, blue | A dot that is missing in one colour but fine in others: one subpixel is stuck or dead. |
| Grey 50% | Faint shapes left behind by apps or icons (burn-in or image retention), and patches that are brighter or darker than the rest. |
| Gradients | Visible stripes or steps instead of a smooth fade (banding). |
| Pixel grid | A fine, even grey texture. Moiré patterns or blur mean the screen is scaling the image instead of showing it pixel for pixel. |
Dead pixel or stuck pixel?
A dead pixel stays dark on every colour, most visible on the white screen. A stuck pixel stays lit in one colour (often red, green or blue) and shows up best on the black screen. Stuck pixels sometimes clear on their own; dead pixels usually do not.
Bleed, glow or burn-in?
- Backlight bleed is light leaking around the edges of an LCD screen. It stays in the same place when you move your head.
- IPS glow is a silvery haze in the corners of IPS screens that changes or fades when you change your viewing angle.
- Burn-in shows up on OLED screens as faint, permanent outlines of things that were on screen for a long time, like a keyboard or navigation bar. Check it on the grey screen.
Found a problem?
Take a photo of the screen showing the issue, note the date, and check the return window of the shop you bought it from. Many manufacturers have a pixel policy that sets how many bad pixels count as a fault, so the number and position matter.
This test runs entirely in your browser. The colours are standard values (pure white #FFFFFF, pure red #FF0000 and so on), and nothing about your screen is sent to us.