Red Screen
Display a full red screen to detect stuck sub-pixels and check color uniformity on monitors, TVs, and phones.
How does this test work?
A red screen test fills your display with pure red to help you detect stuck sub-pixels that appear as different-colored dots, and to check red color uniformity across the panel.
How to use the Red Screen
Open the Red Screen on any device with a modern browser — desktop, laptop, tablet, or phone. No downloads, plugins, or signup required. The tool loads instantly and works in Chrome, Firefox, Safari, Edge, and other Chromium-based browsers.
Follow the on-screen instructions to run the test. Results are displayed immediately in your browser. You can repeat the test as many times as needed. For the most accurate results, close other tabs and applications to reduce interference.
Privacy: This test runs entirely in your browser using standard web APIs. No data is collected, uploaded, or stored on any server. Camera, microphone, keyboard, mouse, and controller inputs are processed locally and never leave your device. DeviceKit does not use analytics cookies or tracking scripts.
Browser note: Some hardware values are estimated because browsers limit direct access to device hardware for security and privacy reasons. Results may vary slightly between browsers and operating systems. For the most reliable measurements, use an up-to-date version of Chrome or Edge on a desktop computer.
Frequently Asked Questions
Why test with a red screen?+
Each pixel has red, green, and blue sub-pixels. A full red screen isolates the red channel, making it easy to spot stuck green or blue sub-pixels that appear as off-color dots.
Related Tests
Dead Pixel Test
Run a free dead pixel test in fullscreen. Check monitors, laptops, phones, tablets, and TVs for dead or stuck pixels using solid color screens.
Green Screen
Display a full green screen to detect stuck sub-pixels and check green color uniformity on your display.
Blue Screen
Display a full blue screen to detect stuck sub-pixels and check blue color uniformity on your display.
Screen Color Test
Cycle through solid colors to test your monitor, TV, or phone for dead pixels, stuck pixels, and color accuracy. Free fullscreen tool.