How this refresh rate test works
The test asks the browser to run a callback before every screen repaint and measures the gap between them for three seconds. The median gap converted to hertz is your refresh rate: a 16.7 ms gap is 60 Hz, 8.3 ms is 120 Hz, and 6.9 ms is 144 Hz. Using the median rather than an average keeps one stalled frame from skewing the result.
Keep this tab in the foreground while it measures. Browsers throttle background tabs to roughly one frame per second to save battery, which would report your expensive gaming monitor as a 1 Hz panel. The test detects that and tells you to run it again.
Why does my 120Hz screen show 60Hz?
Almost always a setting rather than a fault. High-refresh screens frequently ship with the higher mode switched off, or drop to 60 Hz on battery power, in a power- saving mode, or when driven through a cable or port that lacks the bandwidth. Check these in order.
- Windows:Settings → System → Display → Advanced display, then pick the highest rate in “Choose a refresh rate”.
- macOS: System Settings → Displays, and set Refresh Rate away from a fixed 60 Hz.
- Android: Settings → Display → Motion smoothness or Refresh rate, and choose the high setting.
- Battery saver: nearly every laptop and phone caps refresh rate when saving power. Plug in and retest.
- Cable and port: 1440p or 4K at 144 Hz needs DisplayPort or HDMI 2.1. An old HDMI cable will silently limit you to 60 Hz.
- Adaptive rate: phones with LTPO panels drop to 10–60 Hz on static content by design, so a still page can legitimately measure low.
What refresh rate do you actually need?
| Rate | Frame every | Where it shows up |
|---|---|---|
| 60 Hz | 16.7 ms | Standard for office laptops and budget phones; fine for everything but fast games |
| 90 Hz | 11.1 ms | Common on mid-range phones; scrolling feels noticeably smoother |
| 120 Hz | 8.3 ms | Flagship phones, gaming laptops, consoles; the biggest single jump in perceived smoothness |
| 144 Hz | 6.9 ms | The gaming-monitor standard, and the sweet spot for value |
| 240 Hz+ | 4.2 ms or less | Competitive shooters only; diminishing returns for everyone else |
The step from 60 Hz to 120 Hz is dramatic and obvious to almost everyone. The step from 144 Hz to 240 Hz is subtle and mostly matters if you play competitively. If you are choosing a machine, our best gaming laptops guide lists the panel rate for every pick, and best budget phones flags which budget models now include a 90 Hz or 120 Hz screen.
Refresh rate is not frame rate
Refresh rate is how many times per second your screen can redraw, fixed by the hardware. Frame rate is how many frames per second your softwareproduces, and it varies constantly. A 144 Hz monitor showing a game running at 60 fps displays 60 new images a second — the extra capacity sits idle.
That is what this test measures, strictly speaking: the rate at which your browser is presenting frames, which on a healthy idle system equals the display's refresh rate. If the “late frames” count is high, something on the machine is competing for the GPU and the reading will land below your panel's true capability.
Frequently asked questions
Is this refresh rate test accurate?
It is accurate to within a few percent on an idle system in a foreground tab, which is enough to tell 60 Hz from 90, 120 or 144. It cannot exceed what the browser reports, so a handful of browsers that cap animation callbacks will read low — running it twice and comparing is the quickest sanity check.
Why does my reading fluctuate between runs?
Variable refresh rate technologies — FreeSync, G-Sync and phone LTPO panels — deliberately change the refresh rate moment to moment based on content. Background downloads, other tabs and thermal throttling also shift the result. A range of a few hertz between runs is normal.
Can I test a phone's refresh rate this way?
Yes, though adaptive panels complicate it. A phone that idles at 60 Hz on static content may only reach 120 Hz while something is animating, so scroll gently during the measurement and take the higher of several runs as the panel's capability.
What is a good frame time range?
Consistency matters more than the number. On a 60 Hz screen expect a tight cluster around 16.7 ms; wide swings between, say, 8 ms and 40 ms mean uneven pacing, which is perceived as stutter even when the average rate looks correct.