Move the window first
Place this browser window fully on the monitor or screen you want to test before starting, especially in a multi-monitor setup.
TIMING · ESTIMATE · VERIFY
Refresh Rate Test
Estimate the refresh cadence currently reaching this browser window in Hz, then review frame time, timing stability, and run quality.
This is a browser-observed timing estimate. The test does not read your monitor hardware directly, detect its advertised maximum refresh rate, or measure game FPS.
Estimated refresh rate
--Hz
Ready
Ready to test~6 second run
Move this window fully onto the display you want to test. Keep the tab visible while the measurement runs.
0.1.2What this refresh rate test measures
The test measures the timing between consecutive browser animation frames and converts the median interval into an estimated refresh rate. It is designed to answer a practical question: what presentation cadence is this browser window observing on the display where it is currently running?
Keep the test visible
The run is discarded if the tab becomes hidden, the window loses focus, or its size/orientation changes while sampling.
Read the estimate honestly
The result reflects browser presentation timing during this run. Dynamic refresh, power saving, system load, and browser scheduling can change it.
How the test works
After a one-second warm-up, the app records five seconds of requestAnimationFrame() timestamps. It calculates the positive time intervals between frames, uses the median interval as the main estimator, and converts that interval into Hertz.
Estimated Hz = 1000 / median frame interval in milliseconds
Refresh rate vs FPS
Refresh rate describes how often a display path can present updates, usually expressed in Hz. FPS describes how many frames software or content produces per second. They interact, but they are not the same measurement. This app is not a game FPS counter or graphics benchmark.
Refresh rate and frame time
| Rate | Approximate frame interval |
|---|---|
| 60 Hz | 16.67 ms |
| 120 Hz | 8.33 ms |
| 144 Hz | 6.94 ms |
| 240 Hz | 4.17 ms |
Why the result may say 59.9 instead of 60
This is a timing estimate from real browser callbacks, not a label read from monitor firmware. Small fractional differences are normal. The app keeps the raw one-decimal estimate visible and separately shows a closest common rate only when the estimate falls within two percent of that common rate.
Why a 144 Hz or 240 Hz display can appear closer to 60 Hz
The browser only reports what it observes during this run. A lower reading can be associated with operating-system display mode, power saving, multi-monitor behavior, connection configuration, system load, browser scheduling, or dynamic-refresh behavior. The app cannot diagnose which factor is responsible.
Browser timing stability and late browser frames
The stability label is based on median absolute deviation of the observed frame intervals. A late browser frame is an interval longer than 1.5 times the run's median. These are browser timing signals, not proof of dropped monitor frames or a defective display.
Run quality
High, Medium, and Low evaluate whether this particular sample set was stable enough to interpret. Low run quality means repeat the browser measurement; it does not mean the monitor is bad.
Variable refresh rate and dynamic displays
VRR, adaptive-sync systems, dynamic-refresh phones and laptops, and battery-saving modes can change presentation cadence. The result reflects the browser-observed presentation cadence during this test; the app does not claim to detect G-Sync, FreeSync, ProMotion, or a panel's maximum capability.
Multi-monitor testing
Move the browser window fully onto the target display before starting. If you move the window to another display, run a fresh test rather than treating the old result as transferable.
Phones and tablets
The test can run on mobile browsers that provide animation-frame timing, but dynamic refresh and battery-saving behavior may cause the observed cadence to change from one run to another.
What this test does not prove
The result does not prove a monitor's advertised maximum Hz, cable capability, HDMI or DisplayPort certification, GPU performance, game FPS, input latency, pixel response time, ghosting, HDR capability, VRR status, panel quality, or defect status.
Troubleshooting: if a result is unexpectedly low or variable, keep this tab in front, reduce other heavy activity, confirm your operating-system display setting, check power-saving behavior, keep the window fully on the target screen, and run the test again. The app does not assume a cable, GPU, monitor, or browser is automatically at fault.
Worked examples
16.68 ms median: about 59.9 Hz, closest common rate 60 Hz. A fractional difference does not imply a problem.
6.95 ms median: about 143.9 Hz, closest common rate 144 Hz.
Advertised 144 Hz display measuring around 60 Hz: the browser is observing roughly 60 presentations per second in that run. Compare the operating-system refresh setting and repeat under stable conditions before drawing conclusions.
What is my screen refresh rate?
This test estimates the presentation cadence currently observed by this browser window. It does not directly read the monitor's hardware setting.
How does a browser refresh rate test work?
It samples consecutive browser animation-frame timestamps, calculates their intervals, and converts the median interval into an estimated Hz value.
Is refresh rate the same as FPS?
No. Refresh rate concerns display presentation cadence; FPS concerns frames produced by software or media. This app does not benchmark game FPS.
Why does my 144 Hz monitor show about 60 Hz?
The browser may currently be presenting near 60 Hz because of system settings, power mode, connection behavior, multiple displays, browser scheduling, or other load. The app cannot identify the cause automatically.
Can I test 120 Hz, 144 Hz, or 240 Hz?
Yes. The estimator supports common high-refresh timing ranges, provided the browser delivers enough stable samples during the run.
Can I test multiple monitors?
Yes. Move this browser window fully onto one target display and run a fresh test for each display.
Does G-Sync or FreeSync affect the result?
Variable-refresh behavior can affect browser presentation cadence. The app does not detect or certify G-Sync, FreeSync, or VRR state.
Does battery saver affect refresh rate?
It can on some devices. Dynamic-refresh and power-saving systems may lower presentation cadence, so compare runs under the power mode you actually use.
Why does the reading change between runs?
Browser scheduling, system load, power behavior, dynamic refresh, and display changes can all alter timing. Compare runs with the window visible and conditions stable.
What is frame time?
Frame time is the interval between consecutive observed browser animation frames. It is approximately the inverse of refresh rate: 1000 divided by Hz gives milliseconds per frame.
Is this the monitor's maximum refresh rate?
No. It is an estimate of current browser-observed cadence, not a lookup of the panel's advertised or maximum hardware capability.
Does this test response time or ghosting?
No. Pixel response time, motion blur, and ghosting are different display jobs.
Does this measure game FPS?
No. It does not read a game's renderer or graphics pipeline.
Does the test require permission?
No camera, microphone, location, or sensor permission is required.
Is anything uploaded?
The refresh-rate timing result stays in the active browser page. The app does not upload or save the measurement.
Read the refresh-rate guide for a deeper explanation of Hz, frame time, dynamic refresh, and troubleshooting.