This flashes bright colors very fast. Don’t use it if you are sensitive to flashing light.
Clear image retention
This can fade temporary image retention, but it can’t fix permanent burn-in. Noise flickers fast, so skip it if flashing light affects you.
Screen light
Start test tones at a low volume, especially with headphones, and skip the pixel fixer and the noise pattern if flashing light affects you. These tests check your devices, not your hearing or eyesight.
Check a monitor, laptop, TV or phone screen for dead and stuck pixels, backlight bleed and color banding. Fill the whole screen with pure colors, gray levels, gradients and pixel grids, then step through them with a tap or the arrow keys and look closely for dots that don't match. A stuck pixel fixer is included.
How to use
- Pick a tab: Microphone, Webcam, Speakers or Screen.
- Microphone: press Test microphone and allow access. Speak — the meter, wave and status show whether sound arrives. Record 5 s to hear yourself.
- Webcam: press Start camera and allow access. The badge shows the real resolution and measured frames per second; switch cameras or resolutions below.
- Speakers: tap Left, Center or Right. Use the frequency slider or the sweep to check bass and treble.
- Screen: tap a color or start the full-screen test, then tap or press → to step through colors. Look for dots that don’t match.
- The browser asks for permission only after you press a start button. Audio and video never leave your device; recordings are kept in memory until you close the page.
- If no sound is detected, check the mute switch on your headset, the input level in your system sound settings and that the right device is selected.
- Out of phase should sound thin and hard to place. If In phase sounds that way instead, one speaker’s wires are swapped.
- A dead pixel stays black on every color; a stuck pixel stays red, green or blue. The fixer may help stuck pixels after 5–10 minutes, but it can’t repair dead ones.
Dead, stuck and hot pixels
Each pixel has red, green and blue subpixels. A dead pixel stays black on every color, because no subpixel lights. A stuck pixel stays lit in one color, red, green, blue or a mix, and shows best on black or on the opposite color. A hot pixel stays white. Bright or dark specks that move or wipe away are dust, not pixels.
Check every color: dead pixels are easiest to see on white, stuck pixels on black, and a stuck red subpixel stands out on green or blue. Gray levels and gradients show banding and uneven panels; black shows backlight bleed and IPS glow at the edges, best checked in a dark room.
Warranty and the pixel fixer
Many manufacturers accept a small number of defective pixels under the ISO 9241-307 pixel fault classes, so check your warranty terms if you find one. The stuck pixel fixer flashes rapidly changing colors over the screen; running it for 5 to 10 minutes sometimes frees a stuck subpixel. It cannot repair a dead pixel. Skip it if flashing light affects you.
Frequently asked questions
How do I check for dead pixels?
Start the full-screen test and step through each color. Look for a dot that stays black, white or a different color on every background.
What is the difference between a dead and a stuck pixel?
A dead pixel never lights and stays black. A stuck pixel is lit in one color all the time and can sometimes be revived.
Can a stuck pixel be fixed?
Sometimes. Running the pixel fixer for 5 to 10 minutes helps some stuck pixels; dead pixels cannot be fixed by software.
What is backlight bleed?
Light leaking around the edges of an LCD panel, visible on a black screen in a dark room. Some is normal; large bright patches may be covered by warranty.
Is the flashing pixel fixer safe?
It flashes fast and is not suitable for people with photosensitive epilepsy or who are affected by flashing light. Look away while it runs.