Use simulated flicker and motion patterns to look for visible artifacts. A browser cannot directly measure your monitor's PWM backlight frequency or certify a display as flicker-free.
Display simulated flicker patterns and inspect visible artifacts at different frequencies. This browser tool cannot directly measure PWM backlight frequency or certify a monitor as flicker-free.
This tool simulates flickering patterns at different frequencies using requestAnimationFrame. Because the test pattern is rendered by the browser at your display's refresh rate, the actual flicker effect you see is limited by your monitor's Hz. At test frequencies above half your monitor's refresh rate, the pattern will appear as a blended gray. The motion ruler mode shows horizontal moving bars — if your monitor uses PWM dimming, the bars may appear as repeated bright/dark bands due to stroboscopic interaction with the backlight.
Frequency and duty cycle can vary by brightness level and display mode.
DC-style brightness control may reduce temporal modulation, but behavior can vary by product.
Self-emitting panels can still use temporal modulation depending on model and mode.
This page renders patterns for inspection. It cannot read or certify a panel waveform.
Common questions about PWM dimming, flicker-free monitors, and eye strain.
More free tools to check your setup.
Check monitor Hz, 60Hz, 144Hz, 240Hz, frame pacing, and display refresh rate online.
Check your monitor for dead pixels, stuck pixels, and screen uniformity with a full-screen color test.
Check monitor ghosting, motion blur, inverse ghosting, overdrive artifacts, and pixel response online.
Check OLED, AMOLED, and LCD image retention using solid colors, gray screens, and checkerboard patterns.
Measure browser animation-frame timing over 10 seconds using requestAnimationFrame. See average, min, and max FPS with a live bar chart.
Guides on PWM flicker, flicker-free monitors, eye strain, and display ergonomics.
If an online keyboard tester does not detect one key, several keys, or modifier combinations, start with focus, layout, browser shortcuts, rollover limits, and hardware checks.
A browser GPU stress test can reveal crashes, throttling, noisy fans, and WebGL issues, but it cannot replace tools that read sensors, VRAM errors, or driver-level stability.
If a refresh rate test reports 60Hz on a 144Hz or 240Hz monitor, check OS settings, cable limits, browser throttling, VRR, duplicated displays, and power mode.
Mouse polling rate tests can jump between values because of movement speed, DPI, browser event delivery, wireless mode, CPU load, and USB power settings.
If a browser gamepad tester does not detect an Xbox, PlayStation, Switch, or generic controller, check connection mode, browser support, focus, permissions, and Steam input.
If an online microphone test cannot hear you, check browser permissions, the selected input device, OS privacy settings, exclusive mode, Bluetooth headset profiles, and HTTPS.