Input Lag Test
Measure how quickly your browser schedules a new frame after your click, in milliseconds. This is one component of input lag, not your total system latency. Click the target, get your results. No download needed.
What Is Input Lag?
Input lag is the delay between your physical action (like clicking a mouse button) and the response appearing on screen. In gaming this delay can mean the difference between hitting a shot and missing it. This tool measures your browser rendering latency, which is one component of total system input lag.
How to Use the Input Lag Test
Click Start Test
Click the target as soon as you see it appear
Complete all 5 rounds
See your average browser response latency
How to Read Your Result
Your result mainly reflects your display's refresh rate, because the browser schedules a new frame once per refresh cycle. A click can land anywhere inside that cycle, so individual rounds vary by chance and anything up to one frame time is a normal result, not a problem. Consistently higher numbers suggest your browser is under load.
| Your Display | Frame Time | Expected Result |
|---|---|---|
| 60Hz display | 16.7ms per frame | Results from 0-17ms are normal |
| 120Hz display | 8.3ms per frame | Results from 0-9ms are normal |
| 144Hz display | 6.9ms per frame | Results from 0-7ms are normal |
| 240Hz display | 4.2ms per frame | Results from 0-5ms are normal |
What Causes Input Lag?
Total input lag comes from multiple sources: mouse polling rate (1000Hz mouse = 1ms), USB processing, game engine frame time, GPU render time, monitor response time, and monitor refresh delay. This browser test measures JS event and render latency only. For complete input lag testing you need specialized hardware. A higher refresh rate cuts lag too, so check yours with the refresh rate test, and measure your own reflexes with the reaction time test.
How to Reduce Input Lag
- ▸Use a 1000Hz polling rate mouse
- ▸Enable game mode on your monitor
- ▸Use DisplayPort instead of HDMI where possible
- ▸Turn off VSync (adds 1-2 frame delay)
- ▸Close background apps and browser tabs
- ▸Use a wired mouse instead of wireless
- ▸Set your monitor to its maximum refresh rate
Frequently Asked Questions
What does this input lag test actually measure?
It measures the delay between your click event reaching the browser and the next animation frame the browser schedules. That is one small slice of total input lag. It does not include mouse hardware delay, USB polling, operating system processing, or your monitor response time. The result mostly depends on your display refresh rate: values up to one frame time (16.7ms at 60Hz, 6.9ms at 144Hz) are completely normal.
Does input lag affect FPS games?
Yes significantly. In fast-paced FPS games even 20ms of extra input lag can cause you to miss shots that should have connected. This is why competitive players invest in high refresh rate monitors and low latency peripherals.
How is browser input lag different from monitor input lag?
Browser input lag measures how quickly JavaScript and the browser rendering pipeline respond to your click. Monitor input lag measures how quickly pixels change after receiving a signal. Both contribute to total perceived lag.
How do I test input lag online for free?
Use this free online input lag tester. Click Start Test, then click each target the moment it appears across 5 rounds. The tool reports your average browser response latency in milliseconds with no download or signup.
Is input lag the same as reaction time?
No. Input lag is how long your system takes to respond to an input, while reaction time is how long you take to respond to what you see. This test includes your reaction speed, so for a pure reflex measurement try our reaction time test.