Keyboard Latency Test
Measure key-press-to-paint latency in milliseconds, with a distribution of recent samples.
What is Latency Test?
Input latency is how long it takes between pressing a key and seeing the result, and it is the number a typist actually feels. It is also routinely misquoted, because "keyboard latency" usually names only the first stage of a five-stage chain: switch scan, USB polling, the operating system's input queue, the browser's event loop and render, and the display's own refresh. This page measures the whole chain and says so, which makes its numbers larger than a spec sheet's and much more meaningful.
How it works
The timer is `performance.now()` — monotonic, so it cannot jump backwards — captured at keydown and read again two animation frames later, the second frame being the one on screen. Samples are kept as a distribution rather than an average, because the median is what matters and the maximum is what you notice; frames of delay at 60 Hz is reported beside the milliseconds since that is the floor a display imposes before anything else. Every sample is local: nothing is sent anywhere and nothing survives a reload.
- Enter your input. Type or paste your input into the field above — the tool responds instantly.
- Review the result. Output updates live as you type. Everything runs entirely in your browser.
- Copy or download. Use the Copy button to grab the result, or Download to save it as a file.
Examples
Realistic sample
Type or paste any realistic input — the tool computes the result locally and instantly.
Common mistakes
Expecting a server round-trip
Nothing is uploaded — every tool in this category runs entirely in your browser.