Monitor Test

Check your screen for dead and stuck pixels, measure its real refresh rate, and see its resolution and colour support

How to use

1. Clean your screen, then press Start full-screen test.
2. Look closely at each solid colour. Click, tap or press the right arrow to move to the next one, and Esc to finish.
3. Check the refresh rate card to see how many times a second your screen really updates.
4. If you find a pixel stuck on one colour, try the stuck pixel fixer over it for 10 to 20 minutes.

Why use this tool

• Dead and stuck pixel test: Black, white, red, green, blue and grey screens show dead pixels, stuck subpixels and uneven backlighting, with a gradient for colour banding.
• Real refresh rate: Measured from the frames your browser actually draws, with dropped frames left out, then matched to the nearest real panel rate such as 60, 144 or 240 Hz.
• Stuck pixel fixer: A flashing square you can drag over a stuck pixel, or a full-screen flash, behind a clear photosensitivity warning.
• Screen facts: Physical resolution, display scaling, colour depth, colour gamut and HDR support, straight from your browser.

Frequently asked questions

How do I check my monitor for dead pixels?

Clean the screen, start the full-screen test and look at each colour from normal viewing distance, then up close. A dot that stays black on the white screen is a dead pixel; a dot of colour on black or on a different colour is a stuck pixel.

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

A dead pixel gets no power and stays black. A stuck pixel has a subpixel stuck on, so it shows red, green or blue all the time. Stuck pixels can sometimes be freed; dead ones usually cannot.

Can a stuck pixel be fixed?

Sometimes. Running the flashing fixer over it for 10 to 20 minutes, or gently massaging the spot with a soft cloth while the screen is off, frees some stuck pixels. If it does not work, check your warranty, since many makers replace screens with bright stuck pixels.

Why does my 144 Hz monitor show 60 Hz?

Windows or macOS may still be set to 60 Hz, the cable or port may not support the higher rate, or a laptop on battery saver may be limiting it. Set the refresh rate in the display settings, use DisplayPort or a high-speed HDMI cable, and plug in the laptop.

Is the flashing fixer safe?

It flashes very fast, so do not use it if you or anyone nearby is sensitive to flashing lights, and do not stare at it. For the screen itself it is harmless.

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