Keyboard Latency Test.
Estimate your keyboard's input-timing consistency — not true hardware latency — by measuring the jitter between rapid keystroke events.
Click here, then type or mash keys rapidly and steadily — aim for at least a few hundred key events.
Tip: type or roll your fingers at a steady rhythm — an uneven rhythm from you looks like jitter even on great hardware.
Inter-Key Gap Distribution
gap between consecutive keydowns (ms)Timing Stats
Consistency Reference
Check these before you measure
- Go wired firstWireless dongles and Bluetooth add their own delay and jitter; test wired, then compare wireless separately to see the difference.
- Close background appsA busy CPU delays event processing in the browser itself, which shows up here as jitter that has nothing to do with your keyboard.
- Type or mash steadilyAn uneven rhythm from you looks identical to hardware jitter — aim for a smooth, consistent pace, or roll your fingers across the keys.
- Watch the event countA handful of keys won't give a stable reading — the jitter estimate settles in after a few hundred events.
How to measure your input-timing consistency
- 1Focus the capture boxClick the box above so it starts listening for keydown and keyup events.
- 2Type or mash keysType a sentence, or roll your fingers across the letter keys at a steady pace, for at least 10–15 seconds.
- 3Read the jitter and verdictWatch the estimated jitter, average gap, and plain-English verdict update live; press Reset to start a clean run.
What is keyboard latency, really?
"Keyboard latency" usually means the time between pressing a physical switch and the character or action reaching your screen. A web page can only see the moment its JavaScript receives a keyboard event — everything before that (the switch, the controller, USB/Bluetooth transmission, the OS input stack) happens out of sight. So instead of a single latency number, this tool measures how consistent your input timing is: steady, low-jitter gaps between keystrokes suggest a clean path from keyboard to browser; large, erratic gaps suggest something — often wireless, a USB hub, or background CPU load — is adding delay.
This tool timestamps every keydown and keyup event your browser delivers, comparing event.timeStamp against performance.now(). It looks at the gaps between consecutive keydown events and calculates how much those gaps vary (the standard deviation, shown as jitter) rather than trusting any single gap. Because browsers deliberately coarsen and jitter these timestamps for security, and because the true delay between your key switch and the browser event is invisible to JavaScript, treat the result as a relative consistency indicator — not a lab latency measurement.
When this test helps
New wireless keyboard
Compare its jitter in wireless mode against a wired connection to see how much delay the radio link adds.
Diagnosing "laggy" typing
If typing feels inconsistent, a high jitter reading can help confirm it's a timing issue rather than a dropped key.
Before competitive gaming
Check for a steady, low-jitter baseline on your gaming setup, with background apps closed, before a match.
Latency & timing glossary
- Jitter
- Variation between consecutive timing measurements; here, how much the gaps between key events vary rather than staying steady.
- Input lag / latency
- The delay between a physical action and the computer registering it — invisible to a browser at the hardware level.
- Debounce
- A firmware delay that filters switch bounce, which can add a small, consistent delay to every keypress.
- Polling rate
- How often the keyboard reports its state to the PC; a low rate adds latency and can also add jitter.
- Filter keys / slow keys
- An OS accessibility feature that deliberately delays or ignores fast keypresses, which shows up here as very high processing time or jitter.
Frequently Asked Questions
Can a browser really measure keyboard latency?
Not directly. True keyboard latency is the delay between a physical switch closing and your computer acting on it — a chain that runs through the keyboard's controller, USB or wireless transmission, and the operating system before a browser ever sees a KeyboardEvent. JavaScript has no access to any of that. What this tool measures instead is timing consistency: how evenly spaced your keystroke events arrive. It's a useful proxy — a clean, low-latency path tends to produce small, steady gaps — but it is not a substitute for a hardware latency tester.
What is a good jitter score?
As a rough guide, under about 1–2ms of jitter on a steady typing or mashing burst is very consistent — typical of a good wired keyboard with nothing else competing for CPU time. 2–4ms is common and rarely noticeable. Above roughly 4–8ms, or numbers that jump around between runs, suggest something — often a wireless connection, a USB hub, or background load — is adding inconsistent delay.
Why is my jitter worse with a wireless keyboard?
Wireless keyboards (Bluetooth or a 2.4GHz dongle) add an extra radio hop and, on many models, a power-saving polling mode that reports less often and less predictably than a wired connection. Test the same keyboard wired (if it supports it) and wireless, back to back, to see how much the wireless link itself is adding.
Why does closing background apps change the result?
This test runs in your browser's JavaScript engine, which only gets to process a keyboard event when the operating system schedules time for the browser tab. A busy CPU — heavy background downloads, another tab doing heavy work, antivirus scans — delays that scheduling, and the delay shows up here as extra jitter and processing time that has nothing to do with your keyboard's hardware.
What actually causes keyboard input lag?
Several things stack up: a low USB polling rate (the keyboard only reports every few milliseconds), firmware debounce delay (filtering switch bounce), the transmission hop on wireless keyboards, an accessibility feature like Filter Keys or Slow Keys deliberately delaying registration, and finally your display's own input-to-photon delay. This tool can hint at the combined effect through jitter, but can't isolate which single factor is responsible.
Is this the same as an input lag or latency test for a mouse or monitor?
No — the same idea (consistency instead of a true hardware number) applies, but this tool only listens to keyboard events. A mouse click-to-cursor test or a monitor input-lag test would need different measurement points (pointer events, or a photodiode against the physical panel) and isn't something this page measures.
A note on accuracy — this is a consistency check, not a lab measurement
A browser cannot measure true end-to-end keyboard latency: the delay from your finger pressing a physical switch to the OS handing a KeyboardEvent to this page happens entirely outside JavaScript's view, and browsers additionally coarsen and jitter the timestamps they do expose (a deliberate defence against timing attacks). What you see here — average gap, jitter, and processing time — is a RELATIVE indicator of how steady your input timing is, useful for comparing wired vs wireless, before vs after closing background apps, or one keyboard vs another on the same machine. It is not a substitute for a dedicated hardware latency tester or an oscilloscope. For the cleanest reading, use a wired connection, close background apps, and type or mash at a steady pace.