Online monitor test
Check dead pixels, colors, gradients, refresh behavior and motion blur on your display.
Start testWhat can you check?
The monitor test includes patterns for dead or stuck pixels, banding, backlight bleed, uniformity, grayscale, sharpness and motion blur. It also estimates the refresh rate reported through browser frame timing.
Most monitor checks are visual: ACC64 shows the pattern, and you decide what you can see on the panel. A web page cannot automatically confirm a dead pixel or backlight problem without an external camera or sensor.
How to test your monitor
- Clean the screen first so dust is not mistaken for a bad pixel.
- Use the solid-color test in full screen and scan the center, edges and corners.
- Check gradients and gray screens for visible bands, bright patches or uneven tint.
- For refresh rate, keep the tab active and let the measurement settle before reading the result.
How to read the patterns
A good panel should show solid colors evenly, smooth gradients and clearly separated grayscale steps. Motion tests are easier to judge when you track the moving object with your eyes.
For the most reliable result
- Use the monitor's native resolution and normal scaling.
- Darken the room for backlight-bleed checks, but use your normal brightness for most other tests.
- Close heavy apps and other busy browser tabs before checking refresh rate, because dropped browser frames can lower the estimate.
Privacy
The visual tests run in your browser. ACC64 does not capture your screen or require an account.
Frequently asked questions
Can ACC64 automatically detect a dead pixel?
No. The page shows solid colors that make bad pixels easier to see, but you inspect the screen yourself.
Why is the measured refresh rate lower than expected?
Keep the tab active, close heavy apps and let the reading settle. Browser frame timing can drop when the system is busy or power saving is active.
How should I check backlight bleed?
Use the black-screen test in a dark room at a normal viewing angle. Bright patches near the edges can become easier to see.
Do I need to install anything?
No. All test patterns run in a modern browser.
Does ACC64 capture my screen?
No. The monitor test only displays patterns and measures browser frame timing.