Morse Code Timing Explained: Dots, Dashes, Gaps and WPM

Most people meet Morse code as a chart: A is dot-dash, B is dash-dot-dot-dot. That chart is the least useful part of it. Operators do not read dots and dashes, they hear shapes, and a shape only exists if the timing is right. Send an A with a dash that is too short and a trained ear hears an I. This article is about that timing: the small set of rules that turns marks into something a person can actually copy.

The one unit everything is built from

International Morse defines every duration as a multiple of a single unit, the length of one dot. Nothing else is fixed. Speed up the unit and the whole message speeds up in proportion, which is why the rules below hold at 5 words per minute and at 40.

Dot

1 unit of tone.

Dash

3 units of tone.

Gap inside a letter

1 unit of silence between the dots and dashes of the same character.

Gap between letters

3 units of silence.

Gap between words

7 units of silence.

The ratios matter more than the absolute numbers. A dash that is only twice as long as a dot, or a letter gap that is the same as the gap inside a letter, is the most common reason home-made Morse is hard to read: the characters run together and the listener cannot tell where one ends.

What "words per minute" actually counts

A word in Morse speed tests is not any word. By convention it is PARIS, which happens to take exactly 50 units including the 7-unit gap after it. Twenty words per minute therefore means 20 × 50 = 1,000 units a minute, so one unit lasts 60 ms. That gives the handy formula used by almost every trainer and keyer:

Real text runs a little faster or slower than PARIS depending on the letters in it - E is a single dot, while J and Q are long - so WPM is a calibration standard rather than a promise about any particular sentence.

Farnsworth spacing: fast letters, slow sentences

Learning at 5 WPM has a trap. At that speed each letter is so slow that you can count the dots, and counting is exactly the habit that stops people progressing past 10 WPM. Farnsworth timing, named after Donald Farnsworth who popularised it, solves this by sending every character at a brisk speed - often 18 or 20 WPM - and stretching only the gaps between letters and words. The overall pace stays gentle, but each letter keeps the sound it will have at full speed, so you learn the rhythm instead of the count.

In the Morse Code Translator this is the Farnsworth spacing switch: set the character speed with the main WPM slider (5 to 40), then lower the overall speed separately.

Prosigns and the famous exception

A handful of procedural signals are sent as one continuous character with no letter gaps inside. The best known is the distress signal: ···−−−··· - three dots, three dashes, three dots, run together. Written as letters it looks like SOS, but it is sent as a single sign, which is why SOS was chosen: it is unmistakable even through static. Other prosigns work the same way, such as AR (end of message) and SK (end of contact).

Writing Morse down so a translator can read it

When Morse is typed rather than heard, spacing has to be made visible. The convention most tools accept:

Within a letter

No space: .- is A.

Between letters

One space: .- -... is AB.

Between words

A slash with spaces: .- / -... is A B.

Typographic dots and dashes (· and −) copied from documents are usually accepted too, which saves cleaning up pasted text.

A practice routine that trains the ear

1. Pick a character speed of at least 15 WPM and turn Farnsworth on with an overall speed around 5 to 8 WPM.
2. Listen to two or three new letters until you recognise them without thinking, then add more. Never write a dot count down.
3. Play short real words, not random letters - your brain starts predicting, which is how experienced operators read.
4. Raise the overall speed by one or two WPM a week while keeping the character speed the same.
5. Use the .wav download to listen away from the screen, on a walk or a commute.

Sound, light and vibration

Morse was designed for anything that can be switched on and off. Ships used signal lamps, aircraft used light and radio, and a tapped finger works across a table. Hearing it is the fastest way to learn, but seeing the same message as flashes is a good test that you have learned the rhythm rather than the sound of one particular tone. Keep in mind that a phone screen is not a signal lamp: it is fine for practice across a room, not for anything that has to be seen at distance.