Display Test
An all-in-one monitor test: full-screen patterns for colours, banding, colour bars, sharpness, geometry and overscan, convergence, scaling, gamma and viewing angles. Check a new monitor, laptop or TV in five minutes. Free, runs in your browser.
Monitor test patterns
Set the screen to its native resolution and 100% scaling, then start. Each pattern shows its name and what to look for, then the hint fades. Click, tap, swipe or use the arrow keys to step through. Esc exits.
Jump to a pattern
Keys: → ↓ Space Enter next, ← ↑ back, Home and End jump to the first and last pattern, I or H shows the hint again, Esc exits. Patterns are drawn at your device pixel ratio so 1-px lines land on real pixels, but browser zoom or a non-native resolution will blur them. On iPhone Safari, which blocks the Fullscreen API, the test fills the browser window instead.
What each pattern checks
Colours, ramp and colour bars
The five solid screens find dead and stuck pixels, dust and uneven backlighting. The Grayscale ramp shows banding: a cheap 6-bit panel or a bad display profile turns the smooth band into visible stripes, and a crushed dark end merges the first few steps. The colour bars show saturation and edge fringing, and the near-black strips are a quick check for black level.
Sharpness, pixel lines and convergence
The sharpness page mixes 1- and 2-device-pixel stripes with text from 6 to 16 CSS pixels. Sharp text with no halos means scaling is not blurring the image; ringing means sharpening is turned up. The checkerboard turns into moiré when the picture is scaled. The convergence grid shows colour fringes around white lines, which point to a misaligned projector or lens.
Geometry, contrast and viewing angle
On the geometry grid, oval circles mean the wrong aspect ratio or a stretched mode. The gamma patch that matches its stripes is your gamma, and the 1 to 10% and 90 to 99% steps show lost shadow and highlight detail. On the viewing angle page, TN panels darken or invert when seen from below, VA panels shift contrast and IPS panels glow on dark content.
Check a new monitor in five minutes
A five-minute check
Does the panel match the box? Let it warm up for a few minutes, set native resolution, and run every pattern above. Then go deeper where something looked off: the dead pixel test for bad pixels, the black level and white level tests for clipping, the colour range test for a limited-range (16 to 235) mismatch, the gamma test, and the uniformity test for clouding. Do it inside the return window.
Overscan on TVs
Many TVs crop 2 to 5% off every edge and scale the rest up, a habit left over from analogue broadcast. That blurs text and hides the taskbar. If the geometry pattern's white border or 2.5% guide is cut off, set the picture size to "Just Scan", "Screen Fit", "Full Pixel" or "1:1", depending on the brand, and rename the HDMI input to "PC" where offered.
Related tools
- Dead Pixel Test: full-screen colours to find dead, stuck and hot pixels.
- Black Level Test: check shadow detail near black.
- White Level Test: check highlight detail near white.
- Color Range Test: spot full and limited RGB range mismatches.
- Monitor Gamma Test: measure your display gamma.
- Screen Uniformity Test: find clouding and uneven brightness.
Frequently asked questions
How do I leave the full-screen test?
Press Esc at any time. That closes the test, and it leaves full screen if the browser entered it. Previous, X and next sit along the bottom and fade after a few seconds so you can see the edges. Press I or H to show them again, then press X. On a phone with no Esc key, tap once: that moves to the next pattern and brings the buttons back. Then tap X.
Which patterns are on this page?
The solid screens are white, black, red, green and blue, then the Grayscale ramp. After that come colour bars, sharpness and text, geometry and overscan, a convergence grid, pixel lines and a checkerboard, contrast and gamma, and a viewing-angle chart. Start at the first pattern, or open one from its named button.
Why do the fine lines look soft?
Sharpness stripes are 1 or 2 device pixels wide. The pixel-line chart is 1 device pixel, except one checkerboard quarter at 2 device pixels. They stay crisp at the native resolution and 100% scaling. Browser zoom or a non-native resolution scales those lines, so they look soft. Text on the sharpness pattern is set in CSS pixels, from 6 to 16.
Does a smooth ramp mean 10-bit colour or HDR?
No. The gradients are normal browser graphics. This page cannot prove a 10-bit panel, a 10-bit cable or HDR. Steps in the ramp can come from the panel, from scaling, or from a display profile. For a closer banding check, use the colour range test.
What should the geometry pattern show?
Circles should look round and the grid squares should look square. A white border one device pixel thick sits on all four edges, with guides at 2.5% and 5%. If a TV cuts off that border or the 2.5% guide, the set is cropping the picture. Set the picture size to Just Scan, Screen Fit, Full Pixel or 1:1, and name the HDMI input PC where the set offers that.
Why does the test not fill the phone screen?
iPhone Safari blocks the Fullscreen API on an ordinary web page, so the test fills the browser window instead. Turn the phone sideways, or scroll until the address bar tucks away, then start again. Many phones have no Esc key, so leave with the X button.
How is this different from the dead pixel test?
The dead pixel test is solid colours for dead, stuck and hot pixels. This page adds a ramp, colour bars, sharpness, geometry, convergence, gamma patches and a viewing-angle chart. For one fault, use the black level, white level, colour range, gamma or uniformity test linked on this page.