Screen Test
Check your display right in the browser: dead pixels, backlight bleed, shadow and highlight detail, gamma, banding, plus what your browser reports about the screen. Everything runs locally — nothing is uploaded.
This is a visual check, not calibration. Hardware calibration requires a colorimeter.
Screen Report
As reported by your browser — not measured- Resolution
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- Device pixel ratio
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- Color gamut (capability)
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- HDR
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- Color depth (nominal)
- …browsers may always report 24
5-minute guided test (with report card)
Runs black level → white saturation → uniformity → gamma → gradients → archive color pairs, records what you report at each step, and ends with a downloadable report card.
Individual tests
Hue Arrangement Challenge
Drag the middle chips into a smooth left-to-right hue order (the ends are fixed). A score of 0 is perfect.
How to run a meaningful screen test
Prepare the room
Ambient light changes what your eyes can distinguish far more than most people expect. For black-level and uniformity checks, dim the room and avoid light sources behind or beside the display — a lamp reflecting off the panel will mask both backlight bleed and shadow detail. For general color checks, neutral indirect daylight is the most honest environment; avoid strongly colored walls or RGB bias lighting while testing.
Warm up the display
LCD backlights and OLED panels shift slightly in brightness and tint during their first minutes of operation. If you are inspecting uniformity or faint shadow steps, let the screen run for 15–20 minutes first. Laptops on battery may also silently reduce brightness or refresh rate — plug in before testing.
Turn off automatic adjustments
Night Shift, True Tone, f.lux, auto-brightness, battery saver and "eye comfort" modes all rewrite the colors this page asks your screen to show. Disable them for the duration of the test, then re-enable them afterwards. On Windows, HDR mode and Night Light interact — if the report above shows HDR capability, test once with HDR on and once off.
Use native resolution and 100% zoom
Fine test patterns are only meaningful when one pattern pixel maps cleanly onto device pixels. Set the OS to the display's native resolution and your browser zoom to 100% (Cmd/Ctrl+0). If the report above shows a fractional device-pixel-ratio, zoom or OS scaling may be active and fine patterns may look softer than the panel really is.
Clean the screen first
A surprising number of "dead pixels" are dust. Wipe the panel with a dry microfiber cloth before hunting for defects — especially before the solid-color pixel check, where a dark speck on white looks exactly like a dead pixel.
What this page can and cannot tell you
Everything here is a visual check running inside your browser: it can reveal defects (dead pixels, backlight bleed, banding, crushed shadows) and report what the browser says about the display. It cannot measure color accuracy, set gamma, or calibrate anything — real calibration requires a hardware colorimeter that reads light from the panel. Treat results as observations you made, not scores the tool assigned.