Morse code alphabet
S in Morse Code
The letter S in Morse code is ... — spoken "di-di-dit". Press play to hear it, flash it as light, or copy the code.
What does ... mean in Morse code?
... is the letter S in International Morse code. The code is made of 3 dits (short) and 0 dahs (long), which is why it is read aloud as "di-di-dit". It takes 5 time units to send — at a standard 20 words per minute that is roughly 300 milliseconds.
S is three dits and the first letter of SOS. It was chosen for the distress signal precisely because three quick dits are easy to send and hard to misread, even by an untrained operator.
How S is timed
Morse timing is built from one unit — the length of a dit. A dah is three units, and there is one silent unit between the symbols of a letter. Here is S drawn to scale:
How to remember S
Say the phrase si-si-si to the rhythm of the code — the stressed syllables are the dahs, the rest are dits. Hear it a few times with the player above and the phrase will come back by itself.
Easy to confuse with
When you are learning by ear, these codes sound close to S:
Words that start with S
S at a glance
| Morse code | ... |
|---|---|
| Spoken | di-di-dit |
| Symbols | 3 dits, 0 dahs |
| Length | 5 units · ≈300 ms at 20 WPM |
| NATO phonetic | Sierra |
| Frequency in English | ≈6.3% — #7 of 26 letters |
| Position in alphabet | 19 of 26 |
| Reversed | same code backwards (palindrome) |
Frequently asked questions
How do you write S in Morse code?
The letter S is written ... — 3 dits and 0 dahs. Spoken aloud it is "di-di-dit".
What does ... mean in Morse code?
... is the letter S S in International Morse code. If you see or hear "dit dit dit", it stands for S.How long does S take to send?
S lasts 5 time units (a dit is 1 unit, a dah is 3, with 1 unit between symbols). At 20 WPM that is about 300 ms; at a beginner speed of 12 WPM about 500 ms — plus a 3-unit pause before the next character.
What is the NATO phonetic word for S?
In the NATO phonetic alphabet S is "Sierra". Radio operators often say the word and then send ... so the letter cannot be misheard.