CPSForge

Double Click Test

Click slowly, one press at a time. If the mouse reports two clicks from one press, the gap between them will be tiny, and this test flags it.

0Clicks registered
0Suspect doubles
—Last gap (ms)

Gaps over 1 second are not listed. Suspect gaps are marked in red.

Why an old mouse double-clicks

debounce ends 4 ms0 ms16 ms
3.0 msContact settles after
1Clicks reported for 1 press
When metal contacts close they bounce apart and together for a few milliseconds. The mouse ignores changes inside the debounce window (shaded). As a switch wears, the bouncing lasts longer, eventually outlasting the window, and one press arrives as two clicks. A longer debounce hides it, but also caps butterfly and drag clicking. Optical switches have no contact bounce, which is why they can use near-zero debounce.

Questions

How do I test if my mouse double clicks?

Click slowly and deliberately, one press at a time. A healthy mouse shows one event per press. If the test flags gaps shorter than the threshold (80 ms by default) while you only pressed once, the switch is chattering.

Why does my mouse double click when I click once?

The metal contacts in the switch bounce when they close. As the switch wears or oxidises, the bouncing lasts longer than the mouse firmware filters out, so one press is reported as two clicks.

Can I fix a double-clicking mouse?

Often. Raise the debounce or "click response time" in the mouse software if available, blow out dust, or on a wired mouse try a different port. Permanent fixes are replacing the switch or using the warranty.

What threshold should I use?

Humans rarely click the same finger faster than about 80 ms apart on purpose (that would be over 12 CPS). Gaps under 30 ms are almost certainly chatter. Lower the threshold if you are a fast clicker.