GEARCHECK LABMeasure the cadence at which your browser is being given animation frames. The test samples frame intervals for several seconds, estimates the median browser-visible Hz, and shows timing jitter so you can spot obvious mode or throttling problems.
The browser schedules animation callbacks with requestAnimationFrame. Their spacing normally tracks the page's presentation cadence, which often follows the active display refresh mode.
The operating system may be set to another mode, a browser can throttle background/inactive work, battery saving can reduce cadence, and some display paths or remote sessions can cap presentation.
Minor variation such as 143–145 around a nominal 144 Hz mode is normal for a browser-based estimate.
At 60 Hz, an ideal frame interval is about 16.67 ms; at 120 Hz it is about 8.33 ms; at 144 Hz about 6.94 ms. The test reports raw timing spread, a 95th-percentile frame time and long-interval count rather than hiding slow frames or claiming input/pixel-response latency.
Large jitter can come from browser workload, CPU/GPU contention, window compositing or the test environment—not necessarily the monitor.
VRR displays can change their scanout cadence according to content and system behavior. A simple browser animation is not a full G-Sync/FreeSync validation suite and cannot prove the entire VRR operating range.
Refresh rate describes how frequently new frames can be presented. Pixel response time describes how quickly pixels transition. A high-Hz display can still have slow transitions or visible ghosting, so these are separate properties.
Record context with the result. Note the selected operating-system refresh mode, target display, connection path, browser and power mode. A bare Hz number without those conditions is easy to misinterpret.
| Browser-visible result | Likely interpretation | Useful next check |
|---|---|---|
| About 59–60 Hz · 16.67 ms | The browser is probably presenting near a 60 Hz mode. | If you expected more, verify the selected display mode and that the test window is on the intended monitor. |
| About 119–120 Hz · 8.33 ms | The observed cadence is consistent with a 120 Hz presentation mode. | Repeat three times and confirm the p95 stays close to the median interval. |
| About 143–145 Hz · 6.94 ms | A nearby value is normal for a browser estimate of a nominal 144 Hz mode. | Compare consistency rather than demanding an exact integer on every run. |
| About 164–166 Hz · 6.06 ms | The observed cadence is consistent with a nominal 165 Hz mode. | Check that the same cadence remains when the intended cable, port and power mode are used. |
| Stable but lower than expected | The active OS mode, target monitor, cable/adapter path, remote session, power saving or compositor may be limiting presentation. | Check one factor at a time, then repeat the same comparison sequence. |
| WARNING — variable cadence | The sample completed, but its p95 or long intervals did not stay close enough to the median for a clean result. | Close heavy work, keep the page still and visible, then rerun before changing hardware. |
| FAIL — incomplete or unstable sample | The browser did not provide enough usable foreground intervals or no central cadence was trustworthy. | Keep the tab visible, avoid resizing and try a current browser outside remote-desktop or virtual-machine sessions. |
This page observes foreground requestAnimationFrame timing. It cannot read EDID data, monitor firmware, cable certification, true scanout timing, input latency, pixel response, overshoot or the full variable-refresh range.
The live frame intervals and calculated result stay in this page and are not included in analytics events. Opening the page still makes ordinary site requests and may be counted by consented site analytics as explained in the privacy policy.
Use the result to compare browser-visible conditions, not as a manufacturer specification, repair diagnosis or certification. Read the testing methodology and editorial standards for the evidence boundary.
It measures the spacing of foreground requestAnimationFrame callbacks and estimates the presentation cadence visible to this browser tab. It does not read monitor firmware, EDID data or a true hardware scanout counter.
No. It only observes browser frame cadence. Change the actual display mode in your operating-system or graphics-driver settings.
Browsers intentionally throttle or pause animation callbacks in background tabs. Keep the test visible and the window stable for a meaningful sample.
Browser timers, compositing and rounding can produce a nearby estimate such as 143 to 145 Hz. Repeat the sample and compare its median, 95th-percentile frame time and long intervals before treating a difference as meaningful.
No. A browser animation cannot force or verify every variable-refresh-rate condition, minimum or maximum scanout limit, low-framerate compensation mode or vendor-specific feature.
No. Refresh cadence is separate from pixel response, ghosting, input latency, cable reliability and panel condition. Use the focused display tools and external hardware measurements when those properties matter.