Keystroke Latency Test
Measure the delay between a visual cue and your keypress.
Press a key when prompted
Wait for the prompt, then press any key once. Early keypresses cancel that round. Results include browser event timing and your keyboard/device path.
Tool guide
About Keystroke Latency Test
Estimate the interval between a visual cue and a keypress over several rounds. The reading includes screen refresh, browser scheduling, keyboard path, and response time, so it is not a pure measurement of keyboard hardware.
How to use this tool
- 1Start a round and wait for the visual cue.
- 2Press a key once when the cue appears; an early press is marked as a false start.
- 3Complete the five rounds and review the average and individual timings.
How the tool works
The page records `performance.now()` when the cue appears and subtracts it from the time the browser receives a key event. It reports the average across five rounds. Display refresh and keyboard event handling add latency to the result.
Worked real-world example
If a key event arrives 30 ms after the cue timestamp, the page records about 30 ms for that round, including device and browser delays.
Common scenarios and use cases
Compare repeated tests on the same setup or check whether key events reach the browser.
Important details and limitations
This is not a laboratory input-lag test or medical reaction assessment. Wireless links, background load, key repeat, focus, and monitor refresh can affect timing; do not compare casually across devices.
Check the output unit as well as the number. If the result will be reused in another calculation, retain full precision where possible and round only at the end. For measurements governed by a technical specification, use the standard and tolerance required by that document.
Frequently asked questions
Does it measure only the keyboard?
No. The visual and browser path also contribute.
Why are there five rounds?
The page uses repeated measurements to show an average.
Can I press any key?
Yes, the test listens for a keypress after the cue.