Guide
How Many Dead Pixels Are Acceptable on a Monitor
Under ISO pixel class II a 4K monitor can have about 16 bright pixels and still pass. What the standard…
Stuck Pixel Test
Steps through solid colours to find pixels latched on in red, green or blue — the kind that can sometimes be recovered.
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In short
A stuck pixel is one that is latched ON rather than dead, showing a constant red, green or blue dot regardless of what is displayed. It is worth identifying separately from a dead pixel because it is the only one of the two that can sometimes be fixed: the sub-pixel is receiving power and is stuck in one state, and rapidly flashing colours over it can occasionally shake it loose. A dead pixel receives no power at all and nothing shown on screen will change that. The way to tell them apart is the background. Against black, a stuck pixel is an obvious bright dot and a dead one is invisible; against white, a dead pixel is an obvious dark dot and a stuck one nearly disappears. That is why stepping through black, red, green, blue and white is the reliable method rather than staring at one colour. Wipe the screen first — dust on the glass moves when wiped and a pixel fault does not, and mistaking one for the other is the commonest false alarm there is.
How to use the Stuck Pixel Test
- The test starts on its own — no button to press and nothing to install.
- Follow the prompt in the test panel and watch the readings update live.
- Press Reset to start over with a clean slate.
About the Stuck Pixel Test
The Stuck Pixel Test steps through solid colours to find pixels latched on in red, green or blue — the kind that can sometimes be recovered. It runs as plain JavaScript inside the page, which means there is no upload step, no queue and no size limit imposed by a server — the only limit is your own device.
What people use it for
- Finding a bright dot that only appears against dark backgrounds.
- Confirming a fault before trying to unstick it.
Stuck pixels show up most clearly against black. Once you have found one, the Stuck Pixel Fixer on this site is worth running for ten to thirty minutes — it only ever helps stuck pixels, never dead ones.
Explained in our guides
All guidesGuide
How to Check a New Monitor Before the Return Window Closes
Dead pixels, backlight bleed and IPS glow are three different things with three different verdicts. Here is…
Frequently asked questions
What is the difference between a dead and a stuck pixel?
A dead pixel receives no power and stays black on every colour. A stuck pixel is latched on and shows the same bright red, green or blue dot against every background. Stuck pixels sometimes recover; dead ones never do.
How do I tell a dead pixel from dust?
Dust sits on the outside of the glass and moves or disappears when you wipe the screen with a microfibre cloth. A dead pixel does not move and stays in exactly the same position on every colour.
How many dead pixels before I can return a monitor?
That depends on the manufacturer's policy, which is usually written against the ISO 9241-307 pixel fault classes. Most consumer panels are sold to a standard that tolerates several sub-pixel faults, so check the specific warranty terms — and photograph what you find while the panel is still within the return window.
Do I need an account to use the Stuck Pixel Test?
No charge and no sign-up. There is no free tier to run out of because there is no paid tier — inputtesthub.com is funded by advertising rather than by metering the page.
Does anything I enter leave my computer?
No. The Stuck Pixel Test runs entirely in your browser using JavaScript. Your input never reaches inputtesthub.com or any third party — open your browser's Network tab while you use it and you will see no request go out.
Who is the Stuck Pixel Test for?
In practice it gets used for three things: finding a bright dot that only appears against dark backgrounds. Confirming a fault before trying to unstick it. It is built for exactly those cases rather than being a general-purpose tool with this bolted on.
Any caveats I should know about?
Stuck pixels show up most clearly against black. Once you have found one, the Stuck Pixel Fixer on this site is worth running for ten to thirty minutes — it only ever helps stuck pixels, never dead ones.
Do I need to install anything to run this test?
No installation, no extension and no driver. The Stuck Pixel Test uses the browser's own device APIs and begins as soon as the page loads, so there is nothing to press first. Press Reset at any point to start over with a clean slate.
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