240Hz test
Find out whether your screen is actually showing 240 frames per second. Frame time at 240 Hz is 4.17 ms.
Estimated refresh rate
… Hz
- Target frame time
- 4.17 ms
- Measured frame time
- ms
- Long frames (last 240)
Top lane updates at 60 fps, bottom at 240 fps (capped at whatever your display actually shows). If both look the same, you are not getting 240 Hz. For a detailed graph see the full refresh rate test.
Who has 240 Hz displays
Competitive esports monitors at 1080p and 1440p, and many high-end OLED monitors.
Getting 240 Hz working
- Pick 240 Hz in the OS. Windows 11: Settings → System → Display → Advanced display → Choose a refresh rate. macOS: System Settings → Displays → Refresh Rate.
- Cable and port: DisplayPort 1.4 is the usual requirement; 1440p at 240 Hz commonly relies on DSC. HDMI 2.1 also works where the monitor supports it.
- In games, set the in-game refresh rate (if offered) to 240 Hz and make sure the frame rate cap isn't lower.
Browsers can sometimes show lower or uneven readings at 240 Hz and above if the system is busy. Close other tabs and retest.
Other refresh rates: 60Hz test · 75Hz test · 120Hz test · 144Hz test · 165Hz test · 360Hz test
Questions people ask
How do I know if my monitor is running at 240 Hz?
Open this page and wait a few seconds. If the estimate settles near 240 Hz, the browser is receiving 240 frames per second from your display. You can also check Windows Settings → System → Display → Advanced display, or macOS System Settings → Displays → Refresh Rate.
Why does my 240 Hz monitor show a lower number?
Browsers can sometimes show lower or uneven readings at 240 Hz and above if the system is busy. Close other tabs and retest. Also check that the cable goes into the graphics card rather than the motherboard, battery saver is off on laptops, and hardware acceleration is on in the browser.
What cable do I need for 240 Hz?
DisplayPort 1.4 is the usual requirement; 1440p at 240 Hz commonly relies on DSC. HDMI 2.1 also works where the monitor supports it. Exact limits depend on resolution, colour depth and whether the monitor uses Display Stream Compression (DSC), so check your monitor's manual.
Is a browser refresh rate test accurate?
It estimates refresh from requestAnimationFrame timing, which browsers align to the display. It reliably separates 60, 120, 144 and 240 Hz, but it is not a lab measurement, and variable refresh (G-Sync, FreeSync, ProMotion) can move it.