Monitor Tests

Test your monitor in the browser. Find dead and stuck pixels, judge backlight bleed and color uniformity, and measure its real refresh rate. No install needed.

A bad screen rarely fails all at once. A single dark dot sits in one corner. One edge glows on a black frame. A gray desktop looks blotchy instead of even. Each pattern forces one of those faults into the open on a fill where your eye can actually catch it.

Backlight bleed and IPS glow look similar on a dark screen but aren't the same thing. Bleed is light leaking past the panel edges and it holds still when you shift your head. IPS glow brightens in the corners and fades as your angle changes. That's panel behavior, not a defect, and a return won't fix it. A dead pixel lost power and stays black. A stuck one is locked on one color and sometimes comes back. Those two have different fixes and different warranty outcomes.

Most makers set the line at three or more dead subpixels before they accept a claim. Check your warranty before you assume one dot qualifies. Test a new panel the day it arrives, while the return window is open, and photograph any fault for the claim. The refresh rate tool reads what your browser is actually driving. It's the fastest way to catch a 144 Hz panel still running at 60 because of the wrong cable or a Windows setting.

FAQ

How do I test my monitor in the browser?
Open a tool here and put it full screen. Step through the solid color fills and look corner to corner on each one. A dead pixel is a dark dot on a white fill. On black, a stuck one lights up in a single color. Warm the screen up first and dim the room so faint faults stand out. Open the monitor test
Is backlight bleed the same as IPS glow?
No. Backlight bleed is light leaking past the panel edges and it holds still when you move. IPS glow brightens and fades as your angle changes. It's normal for the panel type, not a fault. Bleed can be worth a return; glow usually isn't. OLED panels have neither, since each pixel makes its own light.
How many dead pixels before I can return the monitor?
It depends on the maker. Many set the line at three or more dead subpixels before they accept a claim. A few brands sell zero-tolerance panels that cover even one. Read your warranty, then test and photograph the screen inside the return window. How to check and fix dead pixels
Can a stuck pixel be fixed?
Sometimes. A stuck pixel is locked on one color, and rapidly cycling colors over the spot can knock it loose. A dead pixel gets no power and won't come back. Run the fix for 20 to 30 minutes before you give up.
Why does the refresh rate test read lower than my monitor's rating?
Because something upstream is capping it. A 144 Hz panel can report 60 if the cable can't carry the bandwidth or the Windows display setting hasn't been changed. The test reads what the browser is actually driving, so a low number points you at the cable or settings, not the panel itself. Test the refresh rate
Can I use these to test a TV?
Yes. A TV is just a bigger panel, so dead pixel checks and color fills work the same way, whether you're running them from a browser or a USB stick. Backlight bleed stands out more on a large screen because the corners sit inside your field of view during dark scenes in a way they don't on a desk monitor. How to check your TV color