What is key chatter?
Key chatter is when one press of a key produces two or more characters, like typing "hello" and getting "heello". It is most common on mechanical keyboards with worn or dirty switches, but laptop keyboards can chatter too.
How this test detects chatter
When a switch chatters, it sends a release and then another press only a few milliseconds later, much faster than a finger can move. This tool measures the time between each key's release and its next press. Anything faster than the threshold (40 ms by default) is marked as chatter and the key turns red.
How to fix key chatter
- Blow out dust with compressed air, or remove the keycap and clean around the switch.
- On hot-swappable keyboards, swap in a new switch.
- Increase the debounce time in your keyboard software, if it has that setting.
- Windows Filter Keys can ignore very fast repeats as a temporary workaround.
Frequently asked questions
Why does my keyboard type two letters when I press once?
This is called key chatter. A worn, dirty or faulty switch bounces and sends two presses. Cleaning or replacing the switch usually fixes it.
What threshold should I use?
40 ms catches almost all chatter. If you are very fast at pressing the same key repeatedly, lower it to about 25 ms.
Is key chatter covered by warranty?
Usually yes. Chatter is a common hardware defect. Run this test and note which keys fail before contacting the manufacturer.