Screen tearing test
Vertical black and white bars sweep across the screen at a speed you choose. If the display shows part of one frame and part of the next in the same refresh, the bars break sideways along a horizontal line: that is a tear. Watch for straight bars that suddenly look cut and shifted.
Warning: this test shows fast-moving high-contrast stripes. Do not use it if you are sensitive to flashing or moving patterns.
Running. Use full screen and look at the middle of the screen.
- Frames per second
- —
- Nearest common rate
- —
- Late frames
- 0
- Movement per frame
- —
A tear is a horizontal line where the bars break and shift sideways. Browsers usually wait for the display refresh (VSync), so straight bars are the normal result here; that does not mean games with VSync off will not tear. The page cannot detect tearing automatically.
How to run the test
- Close other busy tabs and apps, then press Full screen. Press Exit full screen or Esc to leave.
- Start with 1920 px/s and 80 px bars. Look at the middle of the screen rather than following a single bar.
- Try the faster speeds: the further the bars move between two frames (shown as Movement per frame), the larger and easier to see a tear becomes.
- Check Frames per second and Nearest common rate: they should match your monitor's refresh rate. If they do not, see the monitor refresh rate test first.
What you will probably see in a browser
Most of the time the bars stay straight. That is expected: Chrome, Edge, Firefox and Safari draw pages through the operating system's compositor, which normally waits for the display's refresh (VSync) before showing a new frame. Without a frame arriving mid-refresh there is nothing to tear.
So a clean result here says the browser path is synchronised. It does not prove that games will not tear: a game running in exclusive full screen with VSync off, or above the range of FreeSync/G-Sync, sends frames whenever they are ready, and that is where tearing usually appears.
If you do see tear lines
- A line that jumps around the screen: frames are being shown without waiting for the refresh. This can happen with some graphics driver settings, remote desktop and screen-sharing tools, or with hardware acceleration turned off in the browser.
- A line that stays in roughly the same place: often a problem in the video path, such as a capture card, a TV processing mode or a mismatch between output and display refresh rate.
- Judder or stutter instead of a tear: the bars jump unevenly but stay straight. That is late or repeated frames, not tearing; check Late frames and the frame skipping test.
- Trails behind the bars: that is slow pixel response, not tearing; use the monitor ghosting test.
Tearing in games: VSync and adaptive sync
- VSync on removes tearing by holding each frame until the next refresh, at the cost of some extra delay and stutter when the frame rate falls below the refresh rate.
- Adaptive sync (FreeSync, G-Sync, HDMI VRR) makes the display wait for the graphics card instead, which removes tearing as long as the frame rate stays inside the monitor's supported range. Check that it is turned on both in the monitor menu and in the graphics driver.
- Above the adaptive-sync range tearing can come back. A frame-rate limit a few frames below the refresh rate is a common way to stay inside the range.
For how refresh rate, frame rate and response time relate, see refresh rate vs response time.
Limits
- The page cannot detect tearing automatically: it only draws the pattern. Your eyes, or a camera, decide.
- The browser cannot turn VSync off, so this is not a substitute for testing in the game that tears.
- Fast-moving high-contrast bars can be uncomfortable. If you are sensitive to flashing or moving patterns, do not use this test. With reduced motion set on your system, the animation starts paused.
Questions
Why don't I see any tearing on this test when I see it in games?
Browsers show pages through the system compositor, which is synchronised to the display's refresh. Games in full screen with VSync off are not, so they can tear when this page does not.
Does FreeSync or G-Sync work in the browser?
Some browsers can use variable refresh rate in full screen, but support depends on the browser, the operating system and driver settings. This page reports the frame rate the browser actually achieves; it cannot tell whether adaptive sync is active.
Is screen tearing a sign that my monitor is faulty?
Usually not. Tearing comes from frames being sent mid-refresh, which is a settings and timing matter. A monitor fault looks different: flicker, lines that stay when the picture is still, or a blank screen.
Related tests
- Refresh rate testMeasures how many frames per second this browser tab draws, with late frames and jitter.
- Frame skipping testA grid that lights one cell per frame; a long-exposure photo shows skipped frames as gaps.
- Ghosting testMoving objects at three labelled speeds on four backgrounds to compare ghosting, smearing and overshoot.
- Dead pixel testFull-screen colours to find dead, stuck and hot pixels on any screen.
- Uniformity testFull-screen greys to spot clouding, vignetting, banding and dirty screen effect.
- Backlight bleed testDark full-screen fields to tell backlight bleed, IPS glow and clouding apart.
- Black & white level testNear-black (1–20) and near-white (235–254) patches to spot black crush and white clipping.
- Gradient testGrey, red, green and blue ramps from 0 to 255 to spot colour banding, with 16–256 step references.
- Screen colour testFull-screen solid colours: red, green, blue, yellow, purple, pink and any custom colour.
- Touch screen testDraw over the whole screen to find dead zones and check multi-touch.
- White screenA plain white full-screen page for checking, cleaning or lighting.
- Black screenA pure black full-screen page to find bright pixels and backlight bleed.
- Red screenA full-screen red light in four brightness levels, from pure red to very dim.
- Pink screenA full-screen pink light in soft shades, for selfies, video calls and backgrounds.
- Lightbox for tracingTurn a tablet or laptop into a bright, even light box that ignores your pencil while you trace.
- Screen lightUse your screen as a soft light for video calls and selfies, in warm, neutral or cool white.
- Online rulerActual-size ruler on your screen in cm, mm and inches, calibrated with a bank card for a real-size scale.