Find keys that type twice when you press them once.
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How to use Key Chatter Tester
Type normally, or tap the key you suspect one press at a time.
Holding a key is ignored, so your operating system's auto-repeat never counts as chatter.
A key that fires twice under the chatter threshold from one press is flagged.
Retest a flagged key a few times before you clean or replace its switch.
About Key Chatter Tester
Check a keyboard for chatter (when one physical keypress registers two or more times). Click into the test box and type normally; if the same key fires again within the chatter threshold, it's flagged in red along with the exact gap.
The operating system's auto-repeat (which kicks in when you hold a key) is ignored, so only genuine sub-threshold re-fires are counted as chatter.
What people use it for
Diagnose a key that occasionally types two characters from one press.
Verify a switch swap or keyboard repair fixed a chattering key.
Confirm a second-hand or returning-from-storage keyboard is reliable.
Frequently asked questions
What is key chatter / double-stroke?
A worn or dirty switch bounces, so a single press is read as several presses. It shows up as doubled letters like 'thhe'.
Does holding a key trigger a false positive?
No. Held-key auto-repeat carries a repeat flag that the tester ignores. Only fresh, fast re-presses of the same key count.
Is it private?
Every calculation happens on this page, in your own browser. Your input is never sent to a server and never logged, which also means the tool keeps working when you are offline.