Refresh Rate (Hz)
    Display · 240 Hz

    240Hz test

    Find out if your monitor is really running at 240Hz. Keep this tab open for a few seconds and the reading settles on your screen's actual refresh rate.

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    About the 240hz test

    Updated

    At 240Hz each frame lasts about 4.2 milliseconds, against 16.7 at 60Hz, which is why a 240Hz monitor feels so much smoother. It's also easy to lose: a cable, port or setting that can't carry 240Hz drops the monitor to 144Hz or 60Hz without any warning. This test times every frame your browser draws and shows the real rate, the nearest standard rate and the frame time, so you can confirm you're getting what you paid for.

    How to use it

    1. Close other tabs and heavy apps, and keep this tab in front.
    2. Wait about five seconds for the reading to settle.
    3. Check the reading shows 240 Hz and a frame time close to 4.2 ms.
    4. If it's lower, set 240Hz in your display settings, check the cable, then measure again.

    Frequently asked questions

    Why is my 240Hz monitor stuck at 144Hz or 60Hz?

    Usually the refresh rate setting in Windows or macOS, a cable or port that can't carry 240Hz at your resolution, or a desktop monitor plugged into the motherboard instead of the graphics card. Our 144Hz guide covers each fix, and they apply to 240Hz too.

    Which cable do I need for 240Hz?

    DisplayPort works with almost every 240Hz monitor. HDMI needs HDMI 2.0 or newer at 1080p, and HDMI 2.1 for 240Hz at 1440p or above, on both the monitor and the graphics card.

    Why does the reading dip below 240?

    At 240Hz the browser has only about 4 ms to draw each frame, so background work causes skipped frames more easily. Close other apps, plug in your laptop and measure again.

    Specific tests

    Guides

    Explainers and fixes that use this test.