Dead Pixel Test Online — Monitor, Phone & TV Screen Check

How to use it

Wipe the screen with a dry cloth and look at the resolution and refresh rate under “Your screen”.

Press “Start full-screen test” and go through the 10 screens by tapping, clicking or using the arrow keys.

When you see a suspicious dot, press “Mark” and tap the dot itself.

At the end, review the list and map of bad pixels and copy the report if you need it.

For a stuck pixel, open the “Stuck pixel fixer” tab, read the warning and run the flashing square over it for 5–10 minutes.

Features

10 full-screen test screens: black, white, red, green, blue, 50% gray, gradients, backlight bleed, sharpness and text

Mark bad pixels with one tap and get a final summary with a list, a map and physical pixel coordinates

Stuck pixel fixer with an RGB or noise flashing square — draggable, resizable, with a 5- or 10-minute timer

Screen info: physical resolution, pixel ratio, aspect ratio, color depth, color gamut, HDR and a refresh-rate estimate

Exact 8-bit gradients drawn pixel by pixel, so you see the panel’s real banding

A 1-pixel frame around the edges to reveal TV overscan

Controls hide after 2 seconds; works with touch, mouse and keyboard and keeps the screen awake

Works on phones, laptops and TV browsers — nothing is uploaded

What this test checks#

A display panel is made of millions of pixels, and each pixel has three sub-pixels: red, green and blue. When the whole screen is filled with one solid color, any pixel that misbehaves stands out as an odd dot. This tool has 10 screens: black, white, red, green, blue and gray to find bad pixels and check uniformity; gradients to reveal banding (colors changing in visible steps); a backlight-bleed screen; a sharpness pattern; and a text sample.

Dead, stuck and hot pixels — what’s the difference?#

Dead pixel: always off. It shows as a black dot on white or colored screens. Its transistor has usually failed, and software can’t fix it.
Stuck pixel: one or two sub-pixels are always on, so you see a red, green, blue or mixed dot — most visible on black. It sometimes recovers with rapid color flashing, which is what this tool’s fixer does.
Hot pixel: all three sub-pixels are always on, giving a bright white dot on black.

A dot that moves when you wipe the screen, or casts a shadow under side light, is dust, not a pixel.

Warranty and pixel policies, explained simply#

Many manufacturers treat a few bad pixels as “normal”. The old basis for this is ISO 13406-2. It was later replaced by the ISO 9241-300 series, but warranty terms still refer to it. Its Class II, which covered most monitors, accepted up to 2 always-on pixels, 2 always-off pixels and 5 faulty sub-pixels per million pixels. A 4K monitor has about 8.3 million pixels, so on paper dozens of dots would be allowed. In practice most brands publish stricter policies, and some offer a “zero bright pixel” guarantee.

So test a new screen on day one, keep proof with “Copy report” or a photo of the screen, and read the warranty terms and the seller’s return window. Returning within the store’s window is usually easier than a warranty claim.

Testing phone and TV screens#

On a phone, turn off auto-brightness and any blue-light filter, then start the test. Safari on iPhone doesn’t allow true full screen for web pages: turn the phone sideways and use aA → Hide Toolbar. On OLED screens a black pixel is simply off, so there is no backlight bleed; instead, look for blotches or a pink or green tint on the gray screen at low brightness.

For a TV, open this page in the TV’s own browser or connect a laptop over HDMI. Set the picture mode to Standard or Movie and turn off processing such as Dynamic Contrast. On the “Sharpness” screen you should see a thin 1-pixel white frame on all four edges. If you don’t, the TV is cropping the picture (overscan) — turn on an option like Just Scan or Screen Fit.

Backlight bleed and IPS glow#

On LCD screens, backlight can leak around the edges. View the “Backlight bleed” screen in a dark room at normal brightness, not maximum. Fixed bright patches in the corners are backlight bleed. A silvery or orange-ish glow that changes as you move your head or change distance is IPS glow — a normal trait of IPS panels, not a defect. Bleed that is strong enough to bother you in dark movies or games is worth a warranty claim.

Tips for an accurate result#

Take a few seconds on each color and scan the screen in strips, especially the corners. The refresh rate shown is a browser estimate; battery-saver modes can hold it at 60 Hz.

Frequently asked questions

Can a dead pixel be fixed?

A true dead pixel (a black dot) usually can’t be fixed with software. A stuck pixel (a colored or white dot) sometimes recovers after a few rounds of this tool’s fixer, but there’s no guarantee. We don’t recommend pressing on the screen — it can make the damage worse.

Is a single dead pixel covered by warranty?

It depends on the brand and the seller. Some brands replace a panel for even one bright pixel; others allow several dots. The best time to act is the store’s return window in the first days after purchase.

Can the fixer damage my screen?

No — it only shows colors, like any video. Because it flashes rapidly, people with epilepsy or light sensitivity shouldn’t look at it. On OLED screens, several short sessions are better than one very long one.

Is anything sent from my device?

No. All tests run in your own browser, and your screen details and markers are never sent anywhere.