How Morse code works
Lesson 1 of 8 · 9 min
Dits, dahs, the timing rules behind them, and why you should learn by sound instead of from a chart.
Morse code turns each letter, digit and punctuation mark into a short pattern of two sounds: a short one and a long one. That is all there is to it. The skill is not memorising the patterns, it is recognising them instantly when you hear them.
This course teaches International Morse Code (the version standardised by the ITU and used by radio operators worldwide). It is not the same as the original American Morse used on early US telegraph lines, which you will rarely meet today.
Dits and dahs
Operators call the short sound a dit and the long sound a dah. On paper they are written as a dot . and a dash -. Say them out loud as you learn: the letter A (.-) is "di-dah", and N (-.) is "dah-dit". The final dit of a character is usually said as "dit", the ones before it as a quick "di".
The two simplest characters are also the most common letters in English: E is a single dit, and T is a single dah.
| Character | Code | Play |
|---|---|---|
| E | dit | |
| T | dah |
Timing is everything
Morse is built from one time unit, the length of a dit. Everything else is a multiple of it:
- Dit: 1 unit of tone.
- Dah: 3 units of tone.
- Gap between the dits and dahs inside one character: 1 unit of silence.
- Gap between characters: 3 units of silence.
- Gap between words: 7 units of silence.
Get the gaps right and Morse is easy to read. Get them wrong and "ET" (. -) turns into "A" (.-), because the only difference is a 3-unit gap versus a 1-unit gap.
Words per minute and PARIS
Speed is measured in words per minute (WPM) using the standard word PARIS, which is exactly 50 units long including the space after it. Sending PARIS 20 times in a minute is 20 WPM. That gives a simple formula: 1 dit = 1200 / WPM milliseconds. At 20 WPM a dit lasts 60 ms, a dah 180 ms, and a word gap 420 ms.
Farnsworth spacing
If you slow everything down to 5 WPM, each character becomes a long, drawn-out pattern that you end up counting ("dit, dit, dah... that is U"). That habit has to be unlearned later. Farnsworth spacing fixes this: each character is sent at full speed (we use 20 WPM), and the extra time goes into the gaps between characters and words. You hear the real rhythm of each letter, and you get time to think between them.
You will see two speeds in this course: the character speed (how fast each letter is sent) and the effective speed (your overall words per minute once the longer gaps are included). As you improve, the character speed stays put and only the gaps shrink.
Learn by sound, not by chart
Charts, trees and picture mnemonics feel fast on day one, but they teach you to translate each sound into dots and dashes and then look them up. That lookup step is why chart learners so often stall at around 10 WPM. Skilled operators do not hear dots and dashes at all: they hear "di-dah" and simply know it is A, the same way you recognise a spoken word.
This course uses the Koch method, developed by the German psychologist Ludwig Koch: start at full character speed with just two characters, and add a new one only when you copy the current set with about 90% accuracy. Each lesson introduces a small group of characters, with drills built only from the ones you already know.