Alphabet · A–Z

S in Morse code

Standard Morse code for S. Copy it, hear it, or practice with real examples.

...

3 signals (3 dots, 0 dashes)Dots are short • dashes are longLetters use spaces • words use “/”

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Memory mnemonic

si-si-si

Say it aloud with the stresses shown. The phrase carries the same dit/dah rhythm as the Morse for S. Once the rhythm sticks the dots and dashes follow.

This is the widely-circulated Scout-meeting variant. Many teachers develop their own — the words don't matter, only that the chosen phrase carries the same dit/dah rhythm.

About S in Morse code

Pattern: ...
Length: 5 Morse units
Spoken as: Sierra (see AIR ah)
In English text: 6.3% of letters — the 7th most common
Sent backwards: reads the same both ways
Dots ↔ dashes: --- is O

S takes 5 units to send. 3 letters are shorter and 2 others are the same length. Alfred Vail reportedly counted the type in a printer's case and gave the shortest codes to the letters used most, so frequency and length roughly track each other: S is the 7th most common letter and has the 4th-shortest code.

How long S takes to send

Speed	Unit length	S takes
5 WPM	240 ms	1.2 s
13 WPM	92 ms	0.46 s
20 WPM	60 ms	0.30 s
25 WPM	48 ms	0.24 s

Standard PARIS timing: one unit is 1200 ÷ WPM milliseconds; a dot is 1 unit, a dash 3, and the gap inside a character 1. Add 3 units between letters and 7 between words.

Easily confused with

These are one dot or dash away from S. Mishearing a single element — or clipping one off the end — turns S into one of them, so they are worth drilling side by side.