Solid full-screen shades · Moving light sweep to reveal hairline scratches · Grid overlay. Set your brightness to maximum. No download.
This tool fills your screen with clean, solid shades and adds a moving light sweep so that scratches, scuffs, and coating wear become visible. Normal app content hides fine damage; a uniform background under bright, angled light exposes it. It is the fastest way to inspect your own phone or to check a second-hand device before you pay for it.
Not every scratch is the same. A line that catches the light and reflects differently as you tilt the device is physical damage to the glass or coating. A fixed dot that never changes is an electrical fault — to check for those instead, use our Dead Pixel Test.
Set your device brightness to maximum, then tap Fullscreen Test to fill the screen with a solid shade and hold the device at a slight angle so light reflects off the glass. Turn on Light Sweep to glide a bright band across the panel — it recreates tilting the phone under a lamp and is the surest way to catch hairline scratches. If you spot damage, switch on Grid Overlay to record its exact location, which is handy when reporting it to a seller.
A surface scratch only marks the oleophobic coating and is visible at an angle but not by touch. A deep scratch reaches the glass, catches a fingernail, and can spread into a crack under pressure. Deep scratches usually mean a glass replacement.
Scratches are invisible head-on but flare when light hits them at an angle. The moving bright band recreates the effect of tilting the phone under a lamp, sweeping across the whole panel so no area is missed — even without a strong light source nearby.
White shows deep scratches and cracks. Black with the sweep on shows coating wear and swirl marks. Gray reveals buffing marks from a previous repair. Cycle all of them for a complete inspection.
Run this test at full brightness before you pay. Note any damage with the grid overlay so you can describe its exact location, and use it as leverage on price. Pair it with our other tests to check the screen end to end.
No web page can scan the physical glass — detection is done by your eyes. This tool gives you the ideal conditions for it: pure solid shades, maximum visible contrast, and a moving light sweep that makes hairline scratches flare. You still do the looking, but it makes hidden damage obvious.
Higher brightness increases the contrast between the flat screen surface and any scratch that scatters light, so faint marks stand out far more. Browsers cannot change your brightness for you, so set it manually in your device settings or control center before testing.
Yes. It runs in any modern browser. On iPhone Safari the fullscreen API is limited, so if the button does not go edge to edge, add the page to your Home Screen or simply hide the browser bars by scrolling. Everything else works the same on all devices.
A scratch is physical damage to the glass or coating — it appears as a line that changes with the viewing angle and reflects light. A dead pixel is an electrical fault in the display itself and appears as a fixed dot that never changes. To check for dead or stuck pixels instead, use our Dead Pixel Test.
Tilt the device and look at the depth of the line. Scratches on a screen protector sit on the very top surface and often have a slightly raised or peeling edge near them. If you are unsure, the safest test is to remove the protector — but in most cases a scratch on a protector is good news, because the protector did its job and is cheap to replace.
Light surface scratches in the oleophobic coating cannot be polished out without removing the coating, but they rarely affect use. Deep scratches in the glass usually require a full screen/glass replacement. Toothpaste and baking-soda "fixes" are myths — they can remove the coating and make things worse. The real protection is a tempered-glass screen protector.