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Screen Tearing Test

Run fullscreen moving patterns and look for horizontal lines where the image splits and shifts sideways. That split is a tear. The test also shows the frame rate your browser is drawing at.

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  • Works in your browser

Test pattern

A tear shows as a horizontal break where the bar edges no longer line up

Faster motion makes a tear wider and easier to see.

Photosensitivity warning

Fast-moving, high-contrast patterns. Skip this if you have photosensitive epilepsy or migraines.

What to look for

  • Tearing: a horizontal line where the top part of a bar or square sits sideways from the bottom part.
  • Stutter: motion that jumps or hitches instead of gliding. That points to dropped frames, not tearing.
  • Blur or trails: smeared edges behind moving bars come from pixel response time, not tearing.
  • Browsers sync their output to the display, so most setups show no tearing here. A clean result does not prove games are tear-free. See the in-game check below.

Keys during the test: Up and Down change speed, Left and Right change the pattern, Esc exits.

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What this test can and cannot show

Browsers sync frames to the display, so the in-game check matters most.

The patterns move sideways at a fixed speed in pixels per second. If a frame is swapped mid-scan, the vertical edges break along a horizontal line, and the faster the motion, the wider that break. The readout in the corner shows how many frames per second your browser is drawing, which should match your monitor's refresh rate.

Browsers present frames with V-Sync on, and a web page has no way to turn it off. Mark Rejhon of Blur Busters described this limit in a W3C proposal for a VSYNC API (opens in new tab). So most setups show no tearing here even when games tear. Use this page to check for stutter, blur, and the right frame rate, then confirm tearing in a game.

  1. Turn V-Sync off in a game and remove any frame cap.
  2. Find vertical edges, like poles or door frames, and turn the camera left and right quickly.
  3. Horizontal breaks in those edges are tears. Turn on V-Sync, FreeSync, or G-Sync and repeat.

How V-Sync, FreeSync, and G-Sync stop tearing

Two ways to line up frame delivery with the monitor's refresh.

Your GPU renders frames independently from your monitor's refresh cycle. When the GPU finishes a frame while the monitor is mid-scan, the display shows part of the old frame and part of the new one. The boundary between them is the tear line.

V-Sync makes the GPU wait for the monitor's vertical blank before swapping frames. That removes tearing but adds input lag, and motion can stutter when the GPU cannot keep up. FreeSync and G-Sync work the other way: the monitor waits for the GPU and changes its refresh rate to match the frame rate, as long as the frame rate stays inside the monitor's variable refresh range.

Above that range, tearing comes back unless V-Sync is also on. Blur Busters' G-SYNC 101 guide (opens in new tab) recommends G-Sync on, V-Sync on in the NVIDIA Control Panel, and a frame cap 3 fps below the refresh rate, such as 141 fps on a 144 Hz monitor.

Screen tearing FAQ

Common questions about tearing, V-Sync, and adaptive sync.

Screen tearing is a horizontal line across the screen where the part above is shifted sideways from the part below. It happens when the GPU swaps to a new frame while the monitor is still drawing the previous one. It is easiest to see during fast sideways camera turns, and the line can jump to a different height every frame.
Look for a horizontal line where the picture above it is shifted sideways from the picture below. It shows up most during fast sideways camera turns or panning shots, and the line can sit at a different height each frame. To confirm it, turn V-Sync, FreeSync or G-Sync on in the same game. If the breaks disappear, it was tearing.
Usually not. Browsers present frames in sync with the display (V-Sync on), and web pages cannot turn that off. Mark Rejhon of Blur Busters notes that Chrome only disables it through a command-line flag, not from JavaScript. So a clean result here does not prove your games are tear-free. If you do see tearing in the browser, check your GPU driver and any compositor or fullscreen optimization settings.
Open a game with V-Sync off and an uncapped frame rate, stand somewhere with vertical edges like poles or door frames, and turn the camera left and right quickly. Tear lines show as horizontal breaks in those edges. Then turn on V-Sync, FreeSync, or G-Sync and repeat. The breaks should disappear.
Use FreeSync (AMD) or G-Sync (NVIDIA) if your monitor supports variable refresh rate, or turn on V-Sync if it does not. Variable refresh rate only removes tearing while your frame rate is inside the monitor's supported range. Blur Busters' G-SYNC 101 guide recommends G-Sync on, V-Sync on in the NVIDIA Control Panel, and a frame cap 3 fps below your refresh rate (for example 141 fps at 144 Hz).
Yes. V-Sync makes the GPU wait until the monitor finishes drawing a frame before it swaps to the next one, which removes tearing. The trade-off is added input lag, plus stutter when your frame rate falls below the refresh rate. FreeSync and G-Sync avoid most of that by changing the monitor's refresh rate to match the frame rate.
No. Screen tearing is a timing artifact in how frames are delivered. It does not damage your monitor or GPU.
No. Tearing is a sync mismatch between the frames your GPU sends and your monitor's refresh, not panel damage. It stops when the two are back in step: turn on V-Sync, FreeSync or G-Sync, or cap your frame rate below the refresh rate.
Your frame rate is probably above the monitor's maximum refresh rate. Above that range, variable refresh stops working and tearing returns unless V-Sync is also on. Cap your frame rate a few fps below the refresh rate and turn V-Sync on in the GPU control panel.

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