Dead pixels and stuck pixels are often confused, but they are different problems.
No power reaches the sub-pixels at all, so the point stays black regardless of what color the screen is showing. This is usually permanent.
One sub-pixel (red, green, or blue) stays permanently on, so the point glows in the same color (for example, always red). In some cases this can fade on its own over time.
A bright colored dot against a black background is more likely a stuck pixel; a point that never reacts to any color is more likely a dead pixel.
You can check both with the step-by-step Screen Tests.
Preparing the scan...
Preparing the test...
Do you see any abnormal spot, line, smudge, or trail on this screen?
ℹ️ This result is based on the answers you gave during the test. A browser cannot automatically detect a physical dead or stuck pixel with full certainty; the result relies on your own observation.
Starting the test...
ℹ️ This measurement is based on real data transferred between your browser and this site's own server. Any value the browser cannot provide is stated honestly; nothing is ever invented.
Waiting for microphone permission...
Speak or make a sound; the level meter should move in real time.
Waiting for camera permission...
Keys you press turn green: 0 / — keys tested.
Inside the test area, click left/right/middle, scroll, and move the mouse.
Play each channel and confirm yourself whether you actually heard it.
ℹ️ The score is calculated only from HTTPS, WebRTC local IP leak, and Do Not Track signals; the other rows are informational only and do not affect the score.
ℹ️ This score is calculated only from signals the browser can safely measure. Real FPS or GPU temperature cannot be measured from a browser and is never shown.
Connect a gamepad and press a button.
Tests browser-visible buttons and analog axes. Vibration is available only when both the controller and browser expose it.
Use the test area below.
Browsers expose scroll signals but cannot reliably tell whether they came from a touchpad or mouse wheel.
Keep this tab visible for an accurate result.
Estimated from animation frames delivered by the browser. It cannot read the monitor's EDID and background tabs are not measured.
Start the approximately 30-second measurement.
Uses repeated HTTPS requests to this site's server, not ICMP packets. “Loss” means an HTTP probe timed out or failed.
Lower your volume before starting.
Short, low-level reference tones only. This subjective check is not an audiogram, hearing test, or medical diagnosis.
Touch the area with several fingers at the same time.
Requires a physical touchscreen. A browser can report touch contacts, but it cannot diagnose the panel's hardware condition.
Start the short browser CPU benchmark.
Runs three identical integer-workload rounds in a background worker. Results are affected by browser, power mode, temperature, and open applications; this is not a full hardware benchmark.
Reading battery information…
Shown only when the browser exposes the Battery Status API. Battery health, wear, and design capacity cannot be read reliably from a web page and are never invented.