Morse Code Translator

Translate text to Morse code and back

Morse code is a character encoding that represents letters, digits, and punctuation as sequences of two signal durations: a short mark called a dit(written ·) and a long mark called a dah (written −). This tool implementsInternational Morse Code, standardized as ITU-R Recommendation M.1677-1, which superseded the original American Morse used on US landline telegraphs.

The timing is defined entirely in multiples of one dit unit, which is what makes the code work at any speed from 5 to 40+ words per minute:

• A dit is 1 unit of signal; a dah is 3 units
• The gap between marks inside one letter is 1 unit
• The gap between letters is 3 units - written as a space here
• The gap between words is 7 units - written as / here

Samuel Morse and Alfred Vail assigned the shortest codes to the most frequent English letters, an early instance of what information theory would later call variable-length coding. Vail reportedly estimated letter frequencies by counting the type in a Morristown newspaper's printer's cases, which is why E is a single dit (·) and T a single dah (−), while rare letters like Q(− − · −) and Y (− · − −) run four marks long.

Is SOS an abbreviation?

No. SOS (· · · − − − · · ·) was adopted at the 1906 Berlin International Radiotelegraphic Convention purely because the nine-mark pattern is unmistakable and hard to garble - the backronyms "Save Our Ship" and "Save Our Souls" were invented afterwards. It is properly sent as one unbroken string with no letter gaps. Related conventions include CQD, the older distress call the Titanic sent alongside SOS in 1912, and the prosign SK (· · · − · −) meaning end of contact.

Morse is no longer required for maritime distress - the Global Maritime Distress and Safety System replaced it in 1999 - but it remains in active use in amateur radio CW operation, in aviation where VOR and NDB navigation beacons continuously identify themselves in Morse, and in assistive technology, where switch-access users with severe motor impairments enter text via two-button Morse input on iOS and Android.

Both directions run locally in this page: encoding maps each character through the ITU table, and decoding parses on spaces and slashes. Nothing you type is uploaded, and there is no length limit.