A white spot on screen usually means a patch that stays lit when everything around it should be dark, or a spot that does not change colour with the rest of the display. This screen test shows full-screen white, black, grey, red, green and blue, then asks three questions to tell you whether it can be fixed.
How to test my screen for a white spot on screen
- Open the box above and start the test. It runs through white, black, grey, red, green and blue, one colour at a time.
- Watch the edges and corners on each colour for a spot, patch or line that does not match the rest of the screen.
- Answer the three questions in the box above to find out whether it is a dead pixel, backlight bleed, a pressure mark, or something fixable.
When to run a screen check
- A new laptop or monitor, checked before the return window closes.
- A second-hand laptop, checked with a quick monitor test before you pay.
- A screen problem that only shows up on dark backgrounds or video.
- A knock or pressure on the lid, to rule out a pressure mark.
What the screen test shows
White and grey make a stuck or dead pixel easy to see. Black shows backlight bleed and light patches near the edges. Red, green and blue isolate one sub-pixel, which is how a colour stuck on gets caught. If your laptop screen looks green in patches, run the green and grey screens together to see if it is a real fault or just a setting.
Limits of this lcd test
It runs in the browser, with nothing to install, free, with no account and no watermark. It runs on our own servers. It cannot repair a screen or settle a warranty claim; it only shows you what is wrong so you know what to say at the service centre.
Questions people ask
What causes a white spot on screen?
It is usually a stuck pixel showing white when it should be dark, or backlight bleed near an edge or corner. Less often it is pressure damage from a knock or something resting on a closed laptop.
Can a white spot on screen be fixed?
A stuck pixel sometimes clears after cycling through colours a few times, which is what this test does. Backlight bleed and pressure marks usually need a technician or a screen replacement.
Why is my laptop screen green?
A green tint across the whole screen often points to a cable or panel fault rather than a setting. Run the grey and white screens; if the tint shows there too, it is likely hardware.
What is a backlight bleed test?
It is a full black screen viewed in a dark room. Any light glowing through, especially near the edges, is backlight bleed, and this test includes that black screen with the other colours.
How is a screen test different from a monitor test?
They check the same thing. Screen test is the term people use for laptop and phone displays, monitor test for a separate screen plugged into a desktop; this tool works for either.
Does a display test work on a phone or tablet?
Yes. Open the box above in the browser on the phone or tablet you want to check and go through the colours the same way as on a laptop.
Updated 24 September 2026.