# Monitor Test > Screen & Dead Pixel Tester · Backlight Bleed & Refresh Rate Check Free online monitor test. Full-screen patterns find dead pixels, stuck pixels, backlight bleed, banding, ghosting and geometry faults. Measure the real refresh rate in Hz, guided wizard, exportable report. No signup, 100% private. URL: https://tools.scoreroute.com/tools/monitor-test/ Markdown: https://tools.scoreroute.com/tools/monitor-test/.md #### Display Stats #### Guided Test ### Why AI Cannot Test Your Monitor A chatbot has no access to the physical pixels on your screen. Display faults such as dead pixels, backlight bleed, colour banding and ghosting are hardware defects that can only be detected by rendering full-screen patterns at the display's native resolution and inspecting them with your own eyes. Asking an AI to "check my screen" only produces advice, never a measurement. This tool renders precise solid-colour fields, gradients, grids and a moving block directly on your display, measures the true frame rate in hertz, and records which patterns show faults — a deterministic hardware diagnosis an AI cannot perform. #### Dead & Stuck Pixel Detection Solid colour fields reveal pixels that stay black or stay locked on one colour #### Backlight Bleed Test Full black screen exposes uneven backlight, IPS glow and corner clouding #### Real Refresh Rate Measurement Counts presented frames to verify true 60/120/144/240 Hz operation #### Stuck Pixel Fixer High-speed colour flashing that revives many stuck pixels in 10-30 minutes ### How the Monitor Test Works Run the solid colours first (black, white, red, green, blue, grey) to look for dead or stuck pixels. Then check the black screen in a dark room for backlight bleed, and the gradient screen for colour banding. Finish with the Refresh Hz test to confirm the panel is running at its rated speed. Do this inside the store return window. Most stuck pixels recover within 10-30 minutes of rapid colour cycling. Leave the fixer running over the affected area and check back occasionally. Stubborn pixels may need two or three sessions. A pixel that stays black on every colour is truly dead and will not respond. Yes. The tool draws patterns in the browser, so it works on any display with a modern browser: laptop panels, desktop monitors, TVs, tablets and phones. The overlay fills the current screen, so rotate or position the device so the full display is visible. The browser can only present frames as fast as the full pipeline supports: the panel, the cable, the GPU and the browser itself. A high setting in the operating system does not guarantee the display actually refreshes that fast. The measured value is what the browser can truly render per second. Yes. The patterns are standard static and gradient fields that OLED owners routinely use to check uniformity and burn-in. The stuck pixel fixer flashes colours rapidly, which is a normal diagnostic technique for OLED and LCD panels, but avoid running any bright full-screen pattern at maximum brightness for extended periods. Policies vary. Some brands replace a panel for a single bright stuck pixel in the central area, while others require several defective pixels or a cluster before replacement. ISO 9241-307 is the common quality reference. Document faults early and inside the warranty period to strengthen your claim. Most manufacturers follow ISO 9241-307 and tolerate a small number of defective subpixels before a screen qualifies for warranty replacement, with stricter limits on premium displays. Test a new monitor inside its return window and document any faults so you can claim a replacement while you still have leverage. - **Press Start Full Screen Test** — the test overlay fills your display at native resolution and hides the cursor so nothing distracts your eye. - **Step through the patterns** — use the on-screen buttons, the ← → arrow keys, or tap the pattern chips. Each pattern reveals a different class of display fault. - **Run the Refresh Hz test** — the tool counts the frames your browser actually presents over several seconds and reports the true refresh rate. - **Export your findings** — generate a report listing which patterns showed issues, then attach it to a warranty or support claim. ## Related Tools - [Webcam & Mic Test](/tools/webcam-test/) - Check your camera, microphone and speakers - [Keyboard Tester](/tools/keyboard-tester/) - Test every key for stuck, ghosting and rollover faults - [Mouse Tester](/tools/mouse-tester/) - Check buttons, double-click chatter and polling rate - [Microphone Test](/tools/microphone-test/) - Measure mic levels, clipping and noise - [Color Contrast Checker](/tools/color-contrast-checker/) - Verify WCAG contrast for your UI colours ## References - [MDN — Canvas API](https://developer.mozilla.org/en-US/docs/Web/API/Canvas_API) - [MDN — HTMLMediaElement](https://developer.mozilla.org/en-US/docs/Web/API/HTMLMediaElement)