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QUEST · LV.05

Monitor & screen test

Measure your real refresh rate and hunt for dead or stuck pixels with full-screen colours.

Runs in your browser · Nothing uploadedFree · No install

Monitor & screen test

Refresh rate

Measuring…

Measured from your browser’s frame timing. Battery saver can lower it.

Resolution

—

Dead pixel test

Fills the screen with solid colours. Click or press → for the next colour, ← to go back, Esc to finish.

Colours change only when you click — no flashing.

Motion clarity

Result

Not tested

Waiting for you to start the test.

How to use

  1. 1Check the measured refresh rate below.
  2. 2Open the full-screen colour test and look for dots that don’t change.
  3. 3Tell us if you found any bad pixels.

Troubleshooting guide

The FreeComTools mascot using a magnifying glass to find a dead pixel on a monitor

Dead, stuck and hot pixels

Clean the screen first — dust looks surprisingly like a dead pixel. Then step through every colour in full screen and scan the panel slowly, section by section.

  • Dead pixel: always black. Most visible on the white screen. Usually permanent.
  • Stuck pixel: always one colour (red, green or blue). Most visible on black or contrasting colours. Sometimes recoverable.
  • Hot pixel: always white/bright. Most visible on the black screen.

Can a stuck pixel be fixed?

Stuck pixels sometimes recover by rapidly cycling colours on that spot for a while, or by very gently massaging the area with a soft cloth while the screen is off. Never press hard. Dead (black) pixels are almost always permanent. Many manufacturers replace panels that exceed a pixel-defect limit within the warranty period — check your model’s pixel policy and take a photo as evidence.

Refresh rate: are you really getting 144 Hz?

A common surprise with new gaming monitors is that they run at 60 Hz out of the box. The number at the top of this page is measured from your browser’s actual frame timing. If it’s lower than your monitor’s spec:

  • Windows: Settings → System → Display → Advanced display → Choose a refresh rate.
  • macOS: System Settings → Displays → Refresh Rate.
  • Use a DisplayPort or a high-speed HDMI cable that supports your resolution and refresh rate.
  • Laptops on battery saver often drop to 60 Hz — plug in and check again.
  • With several monitors, the browser may sync to the slower one. Move this window to the monitor you want to test.

Gradient and banding test

A smooth gradient should look like a seamless ramp. Visible stripes (“banding”) can come from a low colour depth setting, aggressive image modes, or 6-bit panels. Try your monitor’s standard/sRGB mode and make sure your graphics settings output full 8-bit or 10-bit colour.

Backlight bleed and uniformity

On the black screen in a dark room, bright patches at the edges are backlight bleed; a hazy glow that changes with viewing angle is “IPS glow”. Some is normal on LCDs. Strong, distracting bleed in normal lighting can be a warranty issue.

Motion clarity

The motion test moves a shape at a constant speed. On higher refresh rates and faster panels, the shape looks sharper with less blur or ghost trail. Turning on your monitor’s “overdrive” setting can reduce blur, but too high a setting creates bright halos (overshoot).

Frequently asked questions

Is the flashing safe for photosensitive people?

Colours change only when you click or press a key — there is no automatic flashing. If you are sensitive to sudden colour changes, step through slowly or use the gradient test instead.

How accurate is the refresh rate measurement?

It uses the median of hundreds of frame intervals and is usually exact to the nearest standard rate. Background load, battery saver or variable refresh (G-Sync/FreeSync) can affect it.

Why is the resolution different from my monitor’s spec?

We show the resolution your system is currently using, including display scaling. If it’s lower than native, set your display to its recommended resolution.

Can I test a TV or phone screen?

Yes. Open the page on the device (or a computer connected to the TV) and run the full-screen colour test.

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