Fill your screen with solid colors to find dead pixels, stuck pixels and backlight bleed — free, in your browser.
Clean the screen and turn brightness up.
Tap or press → for the next color, ← to go back.
Press Esc or the ✕ button to finish.
Found something? What it means
A black dot on every color — dead pixel
The pixel is not getting power. It will not recover on its own. Check your warranty or return window: many manufacturers replace a screen once it has a set number of dead pixels, so take a photo of it on the white screen.
A colored or white dot on black — stuck pixel
One or more sub-pixels are stuck on. Some recover after the device has been off for a few hours, or with very gentle pressure through a soft cloth while the screen shows black. Never press hard — you can damage the panel.
Light glowing in from the edges on black — backlight bleed
Common on LCD screens (not OLED). Slight bleed visible only in a dark room at full brightness is normal. Bright patches that you notice in everyday use are worth reporting under warranty.
Faint shapes on gray — burn-in or image retention
OLED screens can keep a ghost of things that stay on screen for a long time, like the navigation bar or keyboard. Image retention fades after a while; true burn-in is permanent. Lowering brightness and using dark mode helps prevent more.
Dot moves or wipes away
It is dust or a mark on the glass, not a pixel. Clean the screen and run the test again.
How to test your screen for dead pixels
Wipe the screen with a dry microfiber cloth so dust is not mistaken for a dead pixel.
Turn brightness up and, for backlight bleed, dim the room lights.
Press Start full-screen test. Your screen fills with black.
Scan the whole screen in rows, then tap (or press the right arrow key) to move to the next color. Each color reveals different faults.
When you have seen all six colors, press ✕ or Esc to finish and record what you saw.
Why six colors?
Every pixel is made of red, green and blue sub-pixels. A solid red screen lights only the red ones, so a broken red sub-pixel shows up as a dark dot there while looking fine on other colors. Black shows anything that is lit when it should not be: stuck pixels and light leaking from the backlight. White shows pixels that will not light at all. Mid-gray is the best background for spotting uneven brightness, color tint and OLED burn-in.
When to run a screen test
Straight after buying a new or used phone, tablet, laptop or monitor — while you can still return it.
Before selling a device, so you can describe its screen honestly.
After a drop or a screen replacement.
The test runs entirely in your browser. Nothing is installed, and no image of your screen is captured or sent anywhere.
Frequently asked questions
How do I check my screen for dead pixels?+
Press Start full-screen test, then step through black, white, red, green, blue and gray. A dead pixel shows up as a black dot on the white and colored screens. Look closely, from about 20 cm away, and move your eyes across the screen in rows.
What is the difference between a dead pixel and a stuck pixel?+
A dead pixel gets no power, so it stays black on every color. A stuck pixel has one or more sub-pixels jammed on, so it stays red, green, blue or white — most visible on a black screen. Stuck pixels can sometimes be revived; dead pixels almost never can.
Can this test fix stuck pixels?+
No. This page only shows solid colors so you can find problems. Tools that flash colors rapidly claim to unstick pixels, but results are hit-and-miss, and fast flashing can be unsafe for people with photosensitive epilepsy. If your device is under warranty, report the pixel instead.
Why does the test not go fully full screen on my iPhone?+
Safari on iPhone does not let web pages enter full screen. The test still covers the whole page with each color; turn your phone sideways or scroll slightly so the address bar shrinks, and check the edges separately. iPads support true full screen.
Does this screen test work on monitors and TVs?+
Yes. It works in any modern browser on a phone, tablet, laptop or desktop monitor. On a smart TV or a monitor connected to your computer, open the page in that screen's browser window and press Start.
Is anything sent from my device?+
No. The colors are drawn by your browser and nothing is recorded or uploaded. The test does not need any permissions.
Device Tester app
Test what a browser can’t
Check battery health, sensors, buttons, vibration and charging, then get a full report of your phone — in one free app. Every test runs on your device.
Coming soon on Google Play
More free tests
Touch TestComing soonSwipe across a grid to find dead zones on your touchscreen, and count how many fingers it tracks.
Camera TestComing soonPreview front and back cameras and see the resolution and frame rate you actually get.