Tools

Screen test

Check a new phone, laptop or monitor for dead pixels and light leaks while you can still return it.

PrivateNo uploadsRuns in your browser

Thanks

Refresh rate

–Hz

Measuring…

480 px/s
Resolution
–
Pixel ratio
–
Browser window
–
Colour depth
–
Colour range
–
HDR
–

Full-screen tests

Stuck pixel fixer

Flashing light warning. The fixer flashes bright colours very fast. It can cause seizures in people with photosensitive epilepsy. Do not look at it; place it over the stuck pixel and look away or leave the room.

How to test your screen

  1. Clean the screen

    Wipe off dust first, so a speck is not mistaken for a pixel. Turn brightness up.

  2. Open a full-screen test

    Pick Dead pixels, Backlight bleed, Colour bands, Sharpness or Motion. Tap, swipe or use the arrow keys to change the view.

  3. Check the results

    Note any dots, light patches or stripes. Your refresh rate and screen details are shown at the top.

Good to know

  • Use the arrow keys, a tap or a swipe to change colours. Press Esc to leave full screen.
  • A dust speck moves when you wipe it; a dead pixel never does. Use a soft dry cloth.
  • Check backlight bleed in a dark room with brightness high. Look at the corners and edges.
  • The refresh rate shown is what your browser draws at. Laptops may drop to 60 Hz on battery.
  • For the stuck pixel fixer, run it 10 to 20 minutes, then check again with the red, green and blue screens.

Questions people ask

How do I check my screen for dead pixels?

Open Dead pixels. The whole screen fills with one colour. Look closely at every part of the screen, then tap or press the arrow key for the next colour. A dead pixel stays black on every colour. A stuck pixel stays one bright colour, like red or green.

What is the difference between a dead and a stuck pixel?

A dead pixel gets no power and is always black. A stuck pixel has one colour part stuck on, so it shows as a red, green, blue or white dot. Stuck pixels can sometimes be fixed; dead pixels usually cannot.

Can a stuck pixel be fixed?

Sometimes. The pixel fixer flashes colours quickly over the spot for 10 to 20 minutes, which can wake the stuck part up. It does not always work, and it cannot fix a dead pixel. Read the flashing light warning before you start.

How do I check my monitor's refresh rate?

This page measures it as soon as it opens and shows it at the top, for example 60, 120 or 144 Hz. If you paid for a 144 Hz monitor but see 60 Hz, set the refresh rate in your display settings and use a cable that supports it.

What is backlight bleed?

Light leaking around the edges of an LCD screen. Open Backlight bleed in a dark room with brightness high. Small glow at the corners is common; big bright patches are a fault you can report under warranty.

Why do I see stripes in the gradient test?

Visible steps in a smooth ramp are called banding. Some is normal on cheaper 6-bit screens, with night light or blue light filters on, or in power saving mode. Strong banding on a new screen may mean a low colour setting.

Is my screen HDR or wide colour?

The Your screen panel shows what the browser reports: HDR, colour range (standard, wide P3 or very wide) and colour depth in bits. HDR may only show when HDR is switched on in your system display settings.

Say thanks