Key chatter test
This key chatter test catches keyboard double typing at the hardware level: it times every press of every key and flags any same-key repeat under 45 ms, far faster than any human double-tap. Type normally for a couple of minutes and the per-key table will expose even intermittent chatter.
Presses
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Chatter events
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Session
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Start typing anywhere on this page. Any key that fires twice within 45 ms of itself gets flagged as chatter below.
Auto-repeat from holding a key is ignored; only fresh keydown pairs are counted. Outside the typing box, Space, Backspace, slash and apostrophe are captured so a test press cannot scroll the counter away, navigate back or open quick find. Arrow and Page keys still scroll the page.
| Key code | Presses | Min interval | Chatter (<45 ms) |
|---|---|---|---|
| No presses recorded yet. | |||
Severity guide: under 45 ms = chatter (hardware double-fire). 45 to 80 ms = extremely fast, usually still intentional. Above 80 ms = normal human typing rhythm.
How the chatter test works
Every keydown is timestamped with sub-millisecond precision and compared against the previous press of the same physical key. Two genuine presses of one key arriving less than 45 ms apart get flagged as chatter, because deliberate human double-taps take longer than 80 ms even at competitive typing speeds. Anything between those two numbers shows in the caution color: suspiciously fast, but plausibly intentional. Auto-repeat events from holding a key are filtered out entirely, so held keys can never pollute the result.
The per-key table gives you the evidence, not just a verdict: total presses, the minimum interval ever seen between two presses of that key, and how many of those intervals crossed the chatter line. A single flagged event can be a fluke; a key that racks up chatter counts across a long session has a genuinely bouncing switch.
Why long runs matter
Chatter is the most intermittent keyboard fault there is. A worn switch might double-fire once in fifty presses, and only when struck at a certain angle or speed. That is why the tool includes a long-run typing box and a session clock: type real sentences for about two minutes, lean on the keys you already distrust, and only then read the table. A clean two-minute run is meaningful; a clean ten-second run is not.
Found a chattering key? Before you buy anything, read our key fix guides: compressed air, contact cleaner or a debounce tweak solves many cases, and hot-swap boards let you replace one switch instead of the keyboard. To check the rest of the board while you are here, run the full keyboard tester, verify rollover with the ghosting and NKRO test, or measure your browser's response pipeline with the latency test. If the switch is beyond saving, the switch library helps you pick its replacement.
Frequently asked questions
What is key chatter?
Key chatter, also called double typing or key bounce, is when one physical press registers as two or more keystrokes. Mechanical switch contacts naturally bounce for a few milliseconds on every press; firmware debounce normally filters this out. When contacts wear, oxidize or get dirty, the bounce outlasts the debounce window and doubled letters start appearing in your text.
Why is the chatter threshold 45 milliseconds?
Deliberate human double-taps almost always land above 80 ms apart, and even world-class typists rarely repeat the same key faster than that. A same-key repeat under 45 ms is therefore far outside human range and almost certainly the switch double-firing. The gap between 45 and 80 ms is shown as a caution zone rather than flagged as a fault.
How long should I run the chatter test?
At least two minutes of normal typing. Chatter is intermittent: a worn switch may double-fire once every few dozen presses, so ten seconds of testing proves nothing. Type naturally in the long-run box, work the keys you suspect extra hard, and check the per-key table for any nonzero chatter count.
How do I fix a chattering key?
Start cheap: blow compressed air around the switch, then work the key with rapid presses to reseat the contacts. Contact cleaner applied sparingly into the switch housing helps oxidized contacts. On hot-swap boards, replacing the single bad switch takes a minute. Some keyboard software and firmware can also raise the debounce time as a workaround. Our fix guides walk through each option.
Can auto-repeat from holding a key trigger a false chatter result?
No. The test ignores repeat events that the operating system generates while a key is held down, and only measures the interval between genuine, separate keydown reports of the same key. Held keys therefore never count as chatter here.