LED Test
"LED test" in most readers' searches means a screen test: you suspect a dead, stuck, or discolored pixel on a laptop, phone, or external monitor and want a quick way to confirm it. The tool that actually runs the test is the in-browser LCD / OLED / LED screen test at https://freetoolonline.com/device-test-tools/lcd-test.html; it paints red, green, blue, black, white, and yellow edge-to-edge so a defective sub-pixel stands out as a dot against a uniform field. The same color cycle reads identically across LCD, OLED, and LED panels because the test is about per-pixel response, not backlight type.
Last reviewed: 2026-05-17
| Property | Value |
|---|---|
| Format | Online tool, no install |
| Speed | Browser-side; output in seconds |
| Privacy | Files stay on-device (no upload) |
| Implementing tool | https://freetoolonline.com/device-test-tools/lcd-test.html |
The test itself is one tap per color. Click a color tile (red, green, blue, black, white, or yellow) and the browser paints the chosen color across the full viewport, with an optional Fullscreen toggle on screens 821 pixels wide and larger so the color lifts past the browser chrome and address bar. A stuck pixel near the edge of the panel stays visible at arm's length on a fullscreen field where a tab strip would otherwise hide it. The Reset button drops the overlay so consecutive colors can be swept quickly without a refresh, and the page handles LCD, OLED, and LED panels on phone, laptop, and desktop browsers because the per-pixel response test is panel-type-agnostic.