The number below is measured, not read from a spec sheet: it counts the frames your browser actually presents, right now, on this screen.
Measured refresh rate
measuring
—Hz
frame time —p5 —p95 —
What this measures
Refresh rate is how many times per second your display draws a new image. The test times the browser's frame callbacks — the same clock that drives every animation you see — takes the median interval, and converts it to Hz. Each green bar in the strip is one frame; a flat row of bars at the 120 Hz gridline means a clean, uninterrupted 120. Orange spikes are dropped or delayed frames.
One honest caveat: this is the rate the browser delivers, which is the panel's true rate only when nothing throttles in between. That cuts both ways — it can't detect a 240 Hz panel the OS is running at 120, but it will catch it, which a spec sheet never will.
Reading the result
Reading
Likely reason
What to do
Matches the panel's spec
Everything configured right
Nothing — enjoy it
Exactly 60 on a high-refresh monitor
OS display setting still at its 60 Hz default, or an HDMI cable that can't carry more
Raise it in the OS display settings; prefer DisplayPort on monitors
Lower than spec on a laptop or phone
Battery saver, Low Power Mode, or adaptive refresh idling
Plug in, disable power saving, measure again
Unsteady, with orange spikes
Something is stealing frame time — heavy tabs, background apps, thermal throttling
Close the noise and rerun; if it persists, the benchmark quantifies it
Hz is half the story
A 144 Hz display that misses every third frame feels worse than a steady 60. What your eyes register is frame pacing — the p95 number above tells you how long the slow frames take, and the strip shows whether they cluster. That's why the performance benchmark scores on frame-time percentiles rather than average FPS, and why Refresh rate vs frame time is worth five minutes if you're choosing a monitor.
Keep this page open for a couple of seconds — the number above settles on the rate your browser is actually delivering. Then compare it against the OS setting: Windows keeps it under Settings → System → Display → Advanced display; macOS under System Settings → Displays. If the two disagree, trust the measurement — it’s what your screen is really doing right now.
Why does it say 60 Hz when my monitor is 144 Hz?
Almost always because the monitor is set to 60. High-refresh monitors ship at 60 Hz by default on many systems, and the OS quietly keeps it there — check the display settings first. The second suspect is the cable: older HDMI versions can’t carry 144 Hz at full resolution, while DisplayPort usually can. Battery-saver modes and browser throttling cap it too, but the settings page is where most people find their missing 84 Hz.
How accurate is this measurement?
It’s the median interval between frames the browser presents, snapped to a standard rate when within 5% — so a clean 120 Hz display reads exactly 120. What it can’t see is a rate the browser never delivers: low-power modes, video-driven throttling, or a hidden tab all lower the reading, and the measurement honestly reports that lower number. Measure with the tab in the foreground and the device awake.
Why does my phone show 60 Hz when it has a 120 Hz screen?
Adaptive-refresh phones drop to low rates to save battery and only ramp up when content moves — the animated strip on this page usually wakes them, but power saving wins. iPhones in Low Power Mode cap at 60 Hz outright, and some Android browsers hold web content at 60 regardless of what the panel can do. The panel isn’t broken; the software is being frugal.
Does a higher refresh rate actually matter?
For motion, yes — 120 Hz halves the time each frame lingers, which cuts sample-and-hold blur and makes scrolling and cursor movement visibly smoother. Whether you notice depends on the content: reading static text at 144 Hz looks identical to 60. The full story, including why frame times matter more than the Hz number, is in Refresh rate vs frame time.