What Morse code is and how to learn it

Where Morse code comes from

Samuel Morse and his collaborator Alfred Vail developed the system for the electric telegraph in the late 1830s. In 1844 the first public message was sent over the line between Washington and Baltimore. The original code was not identical to today's: it had, for example, gaps inside some letters.

The Morse used today, international Morse, derives from a simplified version that the German Friedrich Gerke adapted around 1848 for the European telegraph. It removed the internal gaps and became the basis of the standard that kept being used at sea, in the air and on the radio for more than a century.

The timing rule

The whole code rests on a single unit of time, the length of one dot. Everything else is calculated from it. That is why Morse can be sent by light, sound, taps or vibration: what matters is the proportion between signals and silences, not the medium.

Example: the letter O is three dashes with two one-unit gaps between them. It lasts 3 + 1 + 3 + 1 + 3 = 11 units.

How speed is measured: the word PARIS

Morse speed is given in words per minute, but words have different lengths. By convention PARIS is the standard word, because with its internal gaps and the final word gap it lasts exactly 50 units.

• P (.--.) is 11 units, A (.-) is 5, R (.-.) is 7, I (..) is 3 and S (...) is 5: 31 in total.
• Between the five letters there are four gaps of 3 units, which is 12, and at the end a word gap of 7. Sum: 31 + 12 + 7 = 50.
• If you send 20 words per minute, that is 20 × 50 = 1,000 units per minute, so each unit lasts 60,000 ÷ 1,000 = 60 ms. The short formula is 1,200 ÷ words per minute.
• By that math, a full SOS (27 units) lasts 1,620 ms, or 1.62 seconds, at 20 words per minute.

The international Morse alphabet

This table lists the letters and numbers exactly as the tool generates them, with a dot (.) and a dash (-). We don't recommend memorizing it by looking at it: it is for reference, not for learning.

Two useful clues: the most frequent letters are the shortest (E is a single dot, T a single dash), and the numbers follow a pattern, since from 1 to 5 dashes are gradually replaced by dots, and from 6 to 0 the opposite happens.

SOS: what it really is

SOS is written ··· −−− ···: three dots, three dashes, three dots. It was chosen in the early 1900s because it is easy to remember and to recognize. It has one quirk: strictly speaking it is not three letters (S, O and S) but one continuous run of nine signals, without the longer gaps that separate letters.

The tool, on the other hand, works with text: if you type SOS, it produces ... --- ... as three separate letters, with the 3-unit gaps between them. To reproduce SOS in the strict sense you would have to send the nine signals without the letter gaps. It is still fine for practice, and any human receiver recognizes it.

How to learn it: Koch and Farnsworth

The most common mistake is learning the code as a table of dots and dashes and counting them in your head. That works at very low speeds and then becomes a brake. The goal is to recognize each letter as a complete sound, the same way you recognize a spoken word without spelling it out. There are two classic methods.

• Koch method: you learn by ear from the very start, with characters at a high speed (around 20 words per minute is often mentioned). You begin with only two letters and add a new one when you recognize the previous ones with almost no errors. There is nothing to translate mentally because you never saw the letter as dots and dashes.
• Farnsworth method: each letter sounds at its real speed, but the gaps between letters and words are stretched. That gives you time to think without distorting the rhythm of the character. With practice, the gaps are shortened.

With either one, short and frequent sessions (ten or fifteen minutes) work better than one hour on the weekend.

A practice plan with the tool

The Morse code translator uses a single speed for signals and gaps, so it has no Farnsworth setting. You can still practice by ear like this:

1. Type a few repeated letters in the «Text» box, for example ETETEAAT, and watch the Morse appear in «Morse code».
2. Raise the «Speed (words per minute)» control to a value where it is hard to predict the result, and set the «Sound pitch» to one that doesn't tire you.
3. Tap «Play sound» with your eyes closed or covering the Morse box, and try to write down on paper what you hear.
4. Check the result against the original text. When you get almost everything right, add two more letters.
5. For variety, try «Show as light» (full-screen flashes) or «Vibrate» on your phone, which helps you feel the rhythm.

What it is used for today

Morse is no longer mandatory in many fields, but it is still alive. Amateur radio operators use it for telegraphy (CW), because a simple signal can be understood in conditions where a voice gets lost. In aviation, some navigation aids identify themselves with a Morse signal. It is also used as an input method by people with very limited mobility, who type with a single button or switch. And many people learn it for fun or out of curiosity about decoding messages.

Listening to Morse with the microphone, and its limits

In the «Listen to Morse with the microphone» section you tap «Listen with the microphone», allow the browser permission and bring your phone near a sound source. The tool measures how long each tone and each silence lasts, estimates the speed from the shortest tones and shows the text under «What was heard». The audio is analyzed on your device and is not recorded or sent.

The real limits: it works best with a clean tone, little background noise and a steady speed. Morse tapped by hand with an uneven rhythm may be translated incorrectly. If the message has only dashes, the tool can't know the speed. And it only covers the Latin alphabet, with numbers, punctuation and some accented letters: it does not include Cyrillic, Arabic or Japanese. Vibration depends on the browser and works mainly in Chrome for Android.

Frequently asked questions