How Morse Code Works

Last updated:

Mors mascot thinking with a neon-green Morse timing diagram of dots and dashes floating around it
Table of Contents
  1. The Timing Rules
  2. Example: Sending "HI"
  3. Measuring Speed: Words Per Minute (WPM)
  4. Frequency and Tone
  5. Character Design Logic
  6. The ITU Standard
Summarize with ChatGPT Claude Perplexity Grok Google AI Mode

Morse code uses only two signal elements: a short signal called a dit (dot, ·) and a long signal called a dah (dash, —). The entire system relies on precise timing relationships between these elements. Per the ITU-R M.1677-1 standard, one dah lasts exactly three dit units, the gap inside a letter is one dit, between letters three dits, and between words seven dits.

Neon-green timing diagram showing a dot, a gap, and a 3-unit dash, illustrating Morse timing units

The Timing Rules

Everything in Morse code is measured relative to the dot duration, the shortest unit. All other timings are multiples of this unit:

Element Duration Visual
Dot (dit) 1 unit
Dash (dah) 3 units
Gap between elements (within a letter) 1 unit silence
Gap between letters 3 units short pause
Gap between words 7 units long pause
Neon-green signal lamp emitting four short pulses of light, depicting the Morse letter H

Example: Sending "HI"

H = ···· (four dots)

I = ·· (two dots)

Transmission: dit gap dit gap dit gap dit (letter gap) dit gap dit

Units: 1·1·1·1·1·1·1, 3, 1·1·1 = 17 units total

Measuring Speed: Words Per Minute (WPM)

Morse code speed is measured in Words Per Minute (WPM). The standard reference word is PARIS, which contains exactly 50 dot-units when including all internal and word spacing.

This means at 20 WPM, the word PARIS is transmitted 20 times per minute, giving a dot duration of 60ms (1.2 seconds ÷ 20).

Speed Reference

5 WPM: Beginner (dot = 240ms)

13 WPM: Former FCC license requirement (dot = 92ms)

20 WPM: Proficient operator (dot = 60ms)

30 WPM: Expert / contest speed (dot = 40ms)

40+ WPM: High-speed CW (characters blur together)

Mors mascot with headphones over a glowing neon-green sine wave, representing the 600 Hz Morse tone

Frequency and Tone

When transmitted by radio, Morse code is sent as a continuous wave (CW) signal. The receiver produces an audible tone, typically between 400 Hz and 1000 Hz. Most operators prefer a tone around 600–700 Hz, which sits in a comfortable range for the human ear and cuts through background noise effectively.

Character Design Logic

Morse code was designed with efficiency in mind. The most frequently used letters in English have the shortest codes:

E · Most common letter
T — 2nd most common
A ·— 3rd most common
I ·· Vowel
N —· Common consonant
S ··· Common (SOS)
O ——— Common (SOS)
H ···· Common in English

The ITU Standard

The International Telecommunication Union (ITU) maintains the official standard for International Morse Code under Recommendation ITU-R M.1677. This standard defines character assignments, timing rules, and operating procedures used globally.

Ready to start? Learn the proven methods →

Author

MorseKit Team

MorseKit is built and maintained by Firstpoint. Every character table on the site follows ITU-R M.1677-1: the dot and dash ratios, the letter and word gaps, and the ITU punctuation set. One dataset drives the translator, the audio engine and the printable cheat sheets, so a correction reaches all three at once. Alongside International Morse the team maintains nine regional variants, including Wabun, Cyrillic, Greek and Arabic, plus 42 Q codes and 18 prosigns, and the same people build the MorseKit apps for iOS and Android. Where a fact rests on a published standard the guides cite it, and where something has not been verified the page says so.

Share