Cleaning a monitor
A bright, even screen makes dust, smudges and fingerprints obvious. Check first, power the display off, then wipe with a dry microfibre cloth.
Dead pixel test
Run a full dead pixel test straight from your browser. Everything happens on your own device — no upload, no account, nothing installed. It works the same on a phone, a tablet, a laptop screen or a 4K desktop monitor, and it takes under a minute.
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Click the screen or press F. Press Esc to exit. · 100% free. No sign-up. Works offline.
A dead pixel is a single sub-pixel whose transistor has failed. It never lights, so it shows as a black speck on a white field and stays black no matter what the screen is asked to display. A stuck pixel is the opposite fault: the sub-pixel is permanently energised, so it burns red, green or blue against a black field. The distinction matters, because one is permanent and the other can sometimes be revived.
This test cycles the nine fields that between them expose every failure mode: white, black, then pure red, green and blue, then the secondaries and a mid grey. Nine passes take under a minute. Look from about arm's length, then again from close up — a single sub-pixel is roughly a third of a pixel wide and disappears at normal viewing distance.
Clean the screen before you start. At arm's length a speck of dust and a dead sub-pixel are indistinguishable, and dust is by far the more likely explanation.
What this checks
- Dead sub-pixels — permanently black dots, most visible on the white and light fields
- Stuck sub-pixels — permanently lit red, green or blue dots, only visible on black
- Partially stuck pixels that show only on one primary colour
- Clusters of failures, which manufacturers treat far more seriously than single dots
- Dust and grease masquerading as pixel faults, ruled out by the white pass
How to use it
Open the screen
Click or tap the preview panel. Your browser switches to true fullscreen and hides every menu bar and toolbar.
Adjust it
Use the brightness slider and the colour temperature control to get exactly the light you need. Your settings are remembered on this device.
Use it
Clean, test, light or focus. Move the mouse or tap once to bring the controls back at any time.
Exit
Press Esc, or tap the close button in the corner, to return to this page.
What people use it for
Finding dead pixels
A dead pixel stays black on white; a stuck pixel glows red, green or blue on black. Cycling solid colours is still the fastest way to find both.
Video call lighting
A white or warm-white screen beside your face fills in shadows far better than a ceiling light, and costs nothing.
Photography and video
A tablet running a solid colour makes a usable fill light, catch light or small backdrop for product shots.
Tracing and drawing
A tablet on maximum brightness under thin paper works as an improvised light table for tracing and flip-book animation.
Focus and presenting
A blank screen hides your desktop during a presentation and removes visual clutter while you concentrate.
Frequently asked questions
Is the dead pixel test really free?
Yes. Every tool on this site is free, with no account, no trial and no paid tier. You do not need to give us an email address.
Does it work on a phone or tablet?
Yes. The whole site is built mobile-first and works in Safari on iPhone and iPad, Chrome on Android, and every modern desktop browser. On iOS, fullscreen uses a full-viewport mode because Safari restricts the fullscreen API.
Does it work offline?
Yes. After your first visit the page is cached on your device, so you can open it again with no internet connection at all.
Will this damage my screen?
No. Displaying a solid colour is exactly what your screen does all day. The one caution is OLED: leaving a static bright image on an OLED panel for hours can cause temporary image retention, which is why we include an optional burn-in protection mode.
Do you collect my data?
We do not ask for a name, an email or an account, and no image ever leaves your device — every tool renders locally in your browser.
How many dead pixels before a manufacturer replaces the panel?
It varies by brand, model and tier, but a common threshold is somewhere between three and six defective sub-pixels, often stricter in the centre of the screen than at the edges. Almost nobody replaces a panel for a single dead sub-pixel. Check your own manufacturer's dead-pixel policy before starting a claim.
Can a dead pixel be fixed?
A genuinely dead pixel receives no power and cannot be repaired outside a factory. A stuck pixel is different — rapid colour cycling for twenty minutes, or very light massage through a soft cloth on an LCD, revives one often enough to be worth trying.
Do new dead pixels appear over time?
Yes. Panels fail gradually, and a screen that was perfect at purchase can develop a fault years later. It is worth running this test while a new display is still inside its return window.
Guides
How to Test for Dead Pixels (and Tell Them From Stuck Pixels)A five-minute method for finding dead and stuck pixels on any screen, what the difference is, and what your manufacturer will actually replace.How to Fix a Stuck Pixel: What Works and What Does NotStuck pixels can sometimes be recovered with colour cycling or gentle pressure. Here is the realistic success rate and how to avoid making things worse.White Screen of Death: What It Means on a Phone, PC or WebsiteThe same symptom, three completely different causes. How to tell whether a blank white screen is a display fault, a system crash or a server-side error.