Whether you just unboxed a new monitor or you’re troubleshooting an existing one, checking it properly takes a few minutes and doesn’t require installing anything — a handful of free browser-based tools cover dead pixels, response time, and color accuracy.
Testing for dead and stuck pixels
Search for a free “dead pixel test” tool in your browser — the reputable ones simply cycle your full screen through solid colors (red, green, blue, black, white) one at a time, full screen, with nothing else on screen. Go through each color slowly and look closely at the entire panel:
- A pixel that stays black across every color is a dead pixel.
- A pixel that stays one fixed color regardless of what the background is set to is a stuck pixel — these are sometimes recoverable.
Do this in a dim room for the darker colors especially — dead and stuck pixels are much easier to miss under bright ambient lighting.
Fixing a stuck (not dead) pixel
A stuck pixel sometimes responds to rapid color cycling directly on the affected spot — several free “pixel fixing” browser tools do exactly this, flashing colors quickly over a small area. It’s not guaranteed to work, and it does nothing for a genuinely dead pixel, but it’s free, safe to try, and takes only a few minutes.
Explore Our Free PC ToolsTesting response time and ghosting
Free browser-based UFO test tools (widely used and well-established in the monitor enthusiast community) display moving test patterns designed to reveal motion blur and ghosting — trailing artifacts behind fast-moving objects. This is a genuinely useful real-world check because it reflects how the panel behaves during actual movement, which a static spec sheet number can’t fully capture.
If you see heavy trailing at your monitor’s native refresh rate with the test pattern at a normal speed, that’s a meaningful data point — worth comparing against your monitor’s advertised response time rating to see if it’s underperforming its spec.
Checking for color accuracy and uniformity
Free online test patterns for color gradients and grayscale steps can reveal banding (visible steps in what should be a smooth gradient) or panel uniformity issues (patches that look slightly different in brightness or tint from the rest of the screen). These are subtler than dead pixels and often only noticeable once you’re specifically looking for them with a proper test pattern rather than everyday content.
What to do if you find a real problem
- Document it clearly — a photo or screen recording of the specific pixel or pattern issue, taken as soon as you notice it, makes any warranty claim faster.
- Check the return window first if the monitor is new. Most retailers have a simpler, faster return process than a manufacturer warranty claim within the first couple of weeks.
- Check the manufacturer’s specific dead pixel policy before assuming it qualifies — policies vary meaningfully between brands on how many defective pixels are required before it’s covered.
