What Is a Refresh Rate Test?
A refresh rate test estimates how many display update opportunities occur each second. Refresh rate is expressed in hertz: a 60 Hz mode can refresh about sixty times per second, while 144 Hz can refresh about 144 times. This tool samples browser animation intervals, trims the fastest and slowest ten percent, takes a median interval, and converts it to an estimated browser-observed refresh cadence.
The result is not a direct monitor hardware query. Web pages generally cannot read EDID, the physical panel controller, or every operating-system display property. The estimate reflects the cadence exposed to this browser window on the active display. The tool also shows the nearest common standard and rates the match as high, medium, or low confidence based on relative distance.
Refresh Rate vs FPS
Refresh rate describes how often a display mode can update; FPS describes how often an application produces frames. They can be similar when browser animation is synchronized with the display, but they are not the same property. A 144 Hz monitor can show a 60 FPS animation, repeating or holding content between new frames. An application can also render more frames than a fixed-refresh display can present distinctly.
Because browsers normally schedule requestAnimationFrame() near presentation opportunities, a stable callback cadence is a practical estimator for the active refresh mode. It is still an indirect signal. Compositor policy, window placement, system load, remote sessions, and variable refresh behavior can cause the callback rate to differ from the physical display setting.
How to Get Started
Move the entire browser window onto the monitor you want to check. Confirm the display is active, avoid spanning two screens, and close unusually heavy work. Press Measure Refresh Rate and keep the tab visible through warm-up and sample collection. Fullscreen can reduce ambiguity about window placement, though browser and operating-system UI behavior still varies.
- Place the window on one display and select that display’s intended refresh mode in system settings.
- Run the five-second collection without switching tabs or moving the window.
- Compare measured cadence, closest standard, confidence, median interval, and sample count; retest if confidence is low.
How Browser-Based Refresh Testing Works
After a 1.2-second warm-up, the sampler collects positive intervals below one second. At least 120 intervals are required. Sorting and trimming ten percent from each tail reduces the influence of occasional scheduling spikes and unusually short timestamp noise. The median of the remaining set is converted using 1000 / interval, then compared with standards including 59.94, 60, 119.88-adjacent 120, 144, 165, 240, and higher modes.
A result within 0.8 percent of the nearest listed rate receives high confidence; within 2.5 percent receives medium confidence; a larger difference is low confidence. Confidence only describes closeness to a known cadence. It does not certify the monitor or prove that every physical scan occurred at that exact rate.
Why Refresh Rate Results May Vary
If a window spans monitors with different rates, the browser or operating system must choose a presentation strategy. Moving the window can change that choice after a delay. Battery saver, dynamic refresh modes, variable refresh rate, thermal limits, background load, browser throttling, remote desktop software, and screen recording may influence animation callbacks. Some browsers intentionally reduce precision or alter scheduling under specific conditions.
Fractional standards also matter. A mode commonly called 60 Hz may operate near 59.94 Hz, and 120 may be near 119.88. The nearest-standard result keeps those variants visible where useful. Small differences should not be treated as faults. Retest in a quiet foreground session and verify the configured mode in operating-system settings.
Common Refresh Rate Values
Common desktop and mobile modes include 50, 59.94, 60, 72, 75, 90, 100, 120, 135, 144, 165, 180, 200, 240, 280, 300, 360, and 480 Hz. Availability depends on the panel, connection, resolution, color format, graphics hardware, and device mode. A cable or port that supports one combination may not support the same resolution at a higher refresh rate.
Higher refresh can reduce the time between update opportunities and make compatible motion appear more continuous. It does not automatically create new application frames, eliminate all blur, or guarantee lower total input latency. Use the FPS comparison for a visible frame-rate demonstration and the motion clarity test for pursuit-based inspection.
When the Hz Test Helps—and Its Limits
A monitor refresh rate test is useful after changing display settings, connecting a new screen, moving a laptop between power modes, or checking why browser animation appears near 60 FPS. It can reveal that the browser is currently seeing a cadence consistent with a selected mode. Repeat it after the display has settled and keep the same window placement for meaningful comparisons.
The Hz test cannot read monitor firmware, guarantee true scanout, diagnose a cable, prove variable refresh is operating, or measure a native game’s render rate. A high-confidence browser estimate is still an estimate. If it disagrees with system settings, check the active display, resolution and rate combination, browser updates, and another test run before pursuing hardware troubleshooting.