What is Input Lag and Why Does It Matter for Gaming?
Input lag is the total delay between when you perform a physical action (clicking your mouse or pressing a key) and when you see the result on your screen. This delay is a combination of your input device's response time, your computer's processing time, and your monitor's display latency. For competitive gaming, even a few milliseconds of extra input lag can be the difference between landing a headshot and missing entirely.
Total input lag is made up of several components: peripheral latency (how fast your mouse or keyboard sends the signal), USB processing time, game engine processing, render pipeline delay, and display latency. While our browser-based test measures the software and display components of this chain, it gives you a reliable relative measurement to compare settings and identify issues.
How Our Input Lag Test Works
Our test uses a visual stimulus-response methodology. The test area changes color at random intervals, and you click as soon as you see the change. The tool measures the precise time between the visual change and your click using high-resolution performance timers. After 20 rounds, it calculates your average input lag, accounting for your human reaction time.
To get the most accurate results, the test uses requestAnimationFrame timing which synchronizes with your display's refresh cycle. This means the measurements account for your monitor's refresh rate and provide results that reflect your actual gaming experience.
How to Reduce Input Lag
The most impactful way to reduce input lag is to increase your frame rate. Higher FPS means your game processes inputs more frequently, reducing the time between your input and the next rendered frame. This is why competitive gamers prefer 240Hz or 360Hz monitors paired with high frame rates.
Enabling "Game Mode" on your monitor disables post-processing effects that add display latency. Using a wired mouse and keyboard instead of wireless eliminates potential wireless latency (though modern wireless gaming peripherals have largely solved this). Disabling V-Sync removes a significant source of input lag, though it may cause screen tearing.
Input Lag vs Reaction Time
It's important to understand the difference between input lag and reaction time. Reaction time is your body's inherent speed at processing visual information and responding physically, typically 150-250ms for most people. Input lag is the additional delay added by your hardware and software on top of your reaction time. Our test measures the combination of both, but comparing results across different setups with the same person isolates the input lag differences.
Frequently Asked Questions
What is a good input lag for gaming?
For competitive gaming, total system input lag under 20ms is excellent. Under 40ms is good for most games. Above 60ms becomes noticeable and can negatively affect gameplay. Professional esports setups typically achieve 5-15ms of system input lag.
How does monitor refresh rate affect input lag?
Higher refresh rates directly reduce display-related input lag. A 60Hz monitor adds up to 16.7ms of delay per frame, while a 144Hz monitor reduces this to 6.9ms, and a 240Hz monitor to just 4.2ms. This is why competitive gamers invest in high refresh rate monitors.
Does this test measure my monitor's input lag?
Our test measures your total system latency including browser rendering and display output. For pure monitor input lag measurement, specialized hardware tools like the Leo Bodnar lag tester are needed. However, our test is excellent for comparing relative performance between different settings.
Should I turn off V-Sync to reduce input lag?
V-Sync adds significant input lag (often 30-50ms+) because it buffers frames to prevent screen tearing. For competitive gaming, it's generally better to disable V-Sync. If screen tearing bothers you, consider using G-Sync or FreeSync which provide tear-free gaming with minimal added latency.
Why is my input lag higher on a laptop?
Laptops often have higher input lag due to integrated graphics processing, power-saving features that limit CPU/GPU performance, lower refresh rate displays (typically 60Hz), and additional display processing. Gaming laptops with high refresh rate screens and dedicated GPUs significantly reduce this gap.