What is Input Lag?
Input lag (or input latency) is the delay between a physical action (like clicking your mouse) and the resulting action appearing on your screen. In gaming, low input lag is crucial for precision and responsiveness.
How This Browser Test Works
This tool measures browser-level latency. When you click, we record a high-precision timestamp using performance.now(). We then use requestAnimationFrame to detect exactly when the browser's next render cycle completes after your click.
While this doesn't measure your mouse's internal hardware latency, it effectively measures the delay of the browser's event loop, rendering engine, and the VSync signal of your monitor.
Factors Affecting Input Lag
- Monitor Refresh Rate: Higher Hz monitors (144Hz, 240Hz) have much lower sync intervals, significantly reducing lag.
- VSync: Enabling Vertical Sync often adds 1-2 frames of latency to prevent tearing.
- Browser Overhead: Extensions, background tabs, and low-performance hardware can slow down the browser's response time.
- Mouse Polling Rate: Most gaming mice poll at 1000Hz (1ms), while standard mice poll at 125Hz (8ms).