International Morse Code: Complete Reference & Translator

International Morse Code (sometimes called Continental Morse Code) is the globally standardized encoding of letters, numerals, and punctuation as sequences of short (“dots” or dits) and long (“dashes” or dahs) signals. It was codified in 1865 at the International Telegraph Convention in Paris (where the International Telegraph Union, now the ITU, was founded) and is now formalized by the ITU-R M.1677 recommendation. Unlike the older American Morse Code developed by Samuel Morse and Alfred Vail, the international variant uses no internal pauses inside a letter and only two signal lengths, which made it far easier to learn and reliable to transmit over long-distance radiotelegraph circuits.

The code survived the obsolescence of the telegraph because it is remarkably resilient: a single on/off signal (a flashlight, a tapped wall, a radio carrier, even a blinking eye) is enough to carry meaningful text. For more than a century it was the backbone of maritime distress communication, and the famous SOS signal (... --- ...) remains internationally recognized. Even though the International Maritime Organization officially retired Morse for commercial shipping distress in 1999, the code is still used today by amateur radio operators, accessibility tools, pilots, and makers of hidden-message jewellery and tattoos.

Practically speaking, every character is a sequence of dots and dashes with a one-dot pause between symbols, a three-dot pause between letters, and a seven-dot pause between words. Words are usually separated with a forward slash (/) when written down. Read on for the timing rules that hold the whole system together.