Press each key repeatedly — two presses closer than 50 ms count as chatter.
Press each key repeatedly. Two presses closer than 50 ms count as chatter.
Num LockCaps LockScroll Lock
The quick brown fox jumps over the lazy dog, testing your keyboard rhythm.
Esc
F1
F2
F3
F4
F5
F6
F7
F8
F9
F10
F11
F12
~`
!1
@2
#3
$4
%5
^6
&7
*8
(9
)0
_-
+=
Backspace
Tab
Q
W
E
R
T
Y
U
I
O
P
{[
}]
|\
Caps Lock
A
S
D
F
G
H
J
K
L
:;
"'
Enter
Shift
Z
X
C
V
B
N
M
<,
>.
?/
Shift
Ctrl
Win
Alt
Alt
Win
Menu
Ctrl
PrtSc
ScrLk
Pause
Ins
Home
PgUp
Del
End
PgDn
↑
←
↓
→
Num
/
*
-
7
8
9
+
4
5
6
1
2
3
Enter
0
.
CodeKeyRepeatTimestamp
Due to OS-level limits, some keys or combos may not register — this is neither a bug nor a fault of your keyboard. Learn why
On Mac (and some Windows laptops) the F1–F12 keys need a modifier key (e.g. Fn) to work — keep this in mind while testing.
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About this test
Chatter is one physical press being reported as multiple presses — the classic "I typed A once and got AA". It is usually caused by oxidized, worn or dusty switch contacts whose signal flickers at the make-or-break threshold.
How it works: the tester measures the interval between two presses of the same key. A second fire within 50 ms is virtually impossible for a human, so it is counted as chatter; the result line shows both the event count and chatter as a percentage of total presses.
How to test: pick one key — ideally one you suspect — and press it deliberately 20-50 times, then move to the next. A healthy switch stays at zero. If one key keeps chattering, you have found your culprit.
Frequently asked questions
What chatter rate counts as abnormal?
A healthy keyboard should sit near 0%. One or two isolated events can be cleaned and watched; if chatter keeps appearing and the percentage climbs visibly (over about 1%), the switch is worn or contaminated and needs attention.
How do I fix a chattering switch?
Work through these in order: blow into the switch or clean it with a drop of high-purity alcohol → raise the debounce time in the keyboard driver or firmware → replace the switch on a hot-swap board. Under warranty, just file an RMA.
Can the 50 ms threshold produce false positives?
Practically no. Deliberate human re-presses are rarely faster than 100 ms apart, so a second fire within 50 ms is almost certainly contact bounce.