Reaction Time Test (Free Online Latency Checker)
Measure your visual click reaction speed in milliseconds and test display input lag configurations.
Click to Start Test
Click inside this panel to start. Wait for the green color flash, then click instantly!
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Understanding the Science of Reaction Time
Your click score measures the total time it takes for light to enter your eyes, for your brain to process it, and for your muscles to execute a physical click. However, hardware adds layers of delay:
1. Monitor Frame Latency
A standard 60Hz monitor displays one frame every 16.6ms. A fast 240Hz screen drops this frame-generation delay to just 4.1ms, allowing you to see the green transition faster.
2. Peripheral Polling Rate
Standard USB mice poll the OS at 125Hz (8ms delay). A specialized gaming mouse polling at 1000Hz drops signal transfer delay to just 1ms, resulting in cleaner scores.
3. Input Processing Lag
Monitor panels perform internal image processing (scaling, contrast boosters). Game modes or VRR settings (like G-Sync) disable this processing, bypassing 10-30ms of extra lag.
How to Optimize Your Click Speed
- Activate Monitor Game Mode: Open your monitor's physical menu (OSD) and ensure "Game Mode" or "Instant Response" is enabled. This disables post-processing, saving valuable latency.
- Close GPU-Heavy Apps: Background frame loads (like folding calculators, streaming wrappers, or video rendering) increase system input lag.