Refresh Rate Test

How this test works

Browsers repaint the page in step with your display using requestAnimationFrame, which hands each frame a high-resolution timestamp. The test measures the time between consecutive frames — 16.7 ms at 60 Hz, 6.9 ms at 144 Hz — and takes the median over the last 120 frames so one-off stutters don't skew the result. Because measured rates cluster tightly around real panel rates, the result snaps to the nearest standard refresh rate (60, 75, 120, 144, 165, 240…) when it's within a few percent.

The motion strip moves a bar a fixed step every frame. On a healthy setup it glides; if your system drops frames, you'll see it hitch even while the average Hz looks correct — that's the difference between a rate measurement and actual smoothness. The measurement runs entirely in your browser and starts automatically; nothing is uploaded.

Not seeing the refresh rate you paid for?

Set the rate in your OS — it's not automatic

On Windows 11: Settings → System → Display → Advanced display → "Choose a refresh rate", and pick the top value. On macOS: System Settings → Displays → Refresh Rate. If the high rate isn't listed, the OS thinks the link can't carry it — see cable and GPU below.

Check the cable and port

This is the most common cause of a missing high-refresh option. HDMI 1.4 caps 1080p at 120 Hz and 1440p at 75 Hz; you need HDMI 2.0+ or DisplayPort for high refresh at higher resolutions. Use the cable that shipped with the monitor, plug into the discrete GPU's output (not the motherboard's), and on monitors with multiple inputs make sure the active input supports the full rate.

Laptop-specific traps

Battery-saver modes drop refresh dynamically — on Windows 11, "Dynamic refresh rate" under Advanced display, and on many gaming laptops the panel switches to 60 Hz on battery. External monitors on USB-C hubs and docks are frequently limited by the dock's bandwidth even when the laptop's port could do more.

The rate is right but motion still stutters

If the counter reads correctly but the motion strip hitches, frames are being dropped: close other tabs (especially ones playing video), quit GPU-heavy apps, and disable browser extensions in a private window. On multi-monitor setups with mixed refresh rates, Windows historically drives some content at the lower monitor's cadence — testing with a single display connected isolates that.

Frequently asked questions

The test shows 60 Hz but I bought a 144 Hz monitor. Why?

Almost always because the OS is set to 60 Hz — high refresh is not automatic. On Windows 11 go to Settings → System → Display → Advanced display and pick the highest refresh rate; on macOS, System Settings → Displays → Refresh Rate. Also check your cable: older HDMI versions cap high resolutions at 60 Hz, where DisplayPort usually doesn't.

Why does the number fluctuate slightly?

The browser reports frame timing, and a busy system occasionally delays a frame. The test uses the median of the last 120 frames and snaps to common refresh rates, so brief stutters don't change the verdict. If it swings wildly, close heavy tabs and apps and re-run.

Does this measure my monitor or my graphics card?

It measures the rate the browser is actually being driven at — the end result of monitor, cable, GPU, and OS settings together. That is what matters: it is the refresh rate you are really getting, not the number on the box.

My laptop shows a lower rate on battery. Is that a bug?

No — many laptops (and phones) drop the refresh rate on battery to save power. Windows calls it Dynamic Refresh Rate, macOS ProMotion behaves similarly. Plug in and re-run to see the panel's full rate.

Can a browser tab show a different rate than my monitor?

Yes, in specific cases: a background or minimized tab is throttled, some browsers cap frame rate under low battery, and mixed-refresh multi-monitor setups drive the tab at the rate of the display it is on. Keep the tab focused, in the foreground, and on the monitor you want to measure.