What Is a Keyboard Double Click Test?
A keyboard double click test (or key chatter detector) finds keys on your keyboard that register two or more presses when you only pressed once. This is called key chatter and it's caused by worn switch contacts bouncing beyond the keyboard's debounce filter window.
The tool listens for every keydown event, measures the gap between consecutive presses of the same key, and flags any gap shorter than your configured threshold (30-150ms) as a chatter event. You press each key once, slowly; any key showing chatter events double-registered without your input.
Read our full guide on how to fix key chatter once you've identified the affected keys. If a key only repeats while you are holding it down, use the key repeat rate guide instead of treating it as chatter.
How to Read the Results
Total presses
How many times each key registered during the test. If you pressed it once and total says 2, that key is chattering.
Chatter events
Count of times the key registered a second press within the threshold window. Any number greater than 0 means chatter.
Min gap (ms)
Shortest interval between two consecutive presses of that key. Under your threshold = chatter. Healthy typing gaps are 100-200ms+ at normal speeds.
Fix Confirmed Key Chatter
Once this tool confirms which keys are chattering, fix them using one of these approaches (full guide: Keyboard Typing Double Letters? Key Chatter Fix Guide):
- Software debounce (KeyboardChatteringFix on Windows, Karabiner on Mac) — intercepts and filters at OS level.
- Firmware debounce (QMK/VIA keyboards) — increase DEBOUNCE from 5ms to 10-15ms.
- DeoxIT D5 contact cleaner — sprayed into the switch, resolves 60-70% of chatter cases.
- Switch replacement — hot-swap mechanical keyboards: under $1, under 5 minutes.
