Refresh Rate Test
Measure your screen's real refresh rate in Hz.
How the measurement works
Browsers repaint in step with the display, so timing animation frames reveals the true rate: 16.7 ms intervals mean 60 Hz, 6.9 ms mean 144. The test takes the median interval โ robust against the odd dropped frame โ and snaps to the nearest standard rate when close. The moving block makes stutter visible while it runs; close heavy tabs for a clean reading.
If the number is lower than the box promised
This is the test's real job: high-refresh monitors very often ship running at 60 Hz. The refresh rate is a setting, not automatic โ on Windows it is under Display > Advanced display; on macOS, Displays; and it must be set per monitor. A cheap or old HDMI cable can also cap the rate; DisplayPort is the safe choice on high-refresh desktops.
Laptops add wrinkles: many drop to 60 Hz on battery to save power, and phones with adaptive displays legitimately bounce between 60 and 120 depending on what is happening. If the measured number here disagrees with the OS setting, the browser itself may be capped โ some limit background or power-saver tabs. What extra hertz buy you: visibly smoother scrolling and motion, and a real advantage in fast games โ each frame at 144 Hz is drawn ~9 ms sooner than at 60, which is a meaningful slice of a 250 ms human reaction.
Frequently asked questions
How do I know if my monitor is really running at 144 Hz?
Run this test. If it reports 60 on a 144 Hz panel, the OS display setting is almost certainly still on 60 โ it ships that way surprisingly often โ or the cable cannot carry the bandwidth.
Does 144 Hz make a difference?
For fast motion, yes: frames arrive every 6.9 ms instead of 16.7, scrolling looks smoother and games feel more immediate. For static work the difference is minor.
Why does my phone show a changing rate?
Adaptive refresh. Many phones shift between 60 and 120 Hz depending on content to save battery, so the measurement legitimately varies.
Why is the result slightly off, like 59.9?
Many "60 Hz" displays actually run at 59.94 Hz for historical television reasons. The test snaps to the nearest standard rate when it is close.