Reference · International Morse code
Morse Code Guide
Morse code represents each letter, figure, and sign as a pattern of short signals (dots, written “.”) and long signals (dashes, written “−”). This guide lists the international code and the spacing rules for sending it.
- Standard
- ITU-R M.1677-1 (10/2009)
- Dot
- One unit long, written “.”
- Dash
- Three units long, written “−”
- Checked
- 2026-11-01
Spacing rules
| Element | Length |
|---|---|
| Dot | 1 dot unit |
| Dash | 3 dot units |
| Space between signals in one letter | 1 dot unit |
| Space between two letters | 3 dot units |
| Space between two words | 7 dot units |
Source: ITU-R M.1677-1, section 2 (spacing and length of the signals).
Letters
| Letter | Signal | Spoken |
|---|---|---|
| A | .− | dit dah |
| B | −... | dah dit dit dit |
| C | −.−. | dah dit dah dit |
| D | −.. | dah dit dit |
| E | . | dit |
| F | ..−. | dit dit dah dit |
| G | −−. | dah dah dit |
| H | .... | dit dit dit dit |
| I | .. | dit dit |
| J | .−−− | dit dah dah dah |
| K | −.− | dah dit dah |
| L | .−.. | dit dah dit dit |
| M | −− | dah dah |
| N | −. | dah dit |
| O | −−− | dah dah dah |
| P | .−−. | dit dah dah dit |
| Q | −−.− | dah dah dit dah |
| R | .−. | dit dah dit |
| S | ... | dit dit dit |
| T | − | dah |
| U | ..− | dit dit dah |
| V | ...− | dit dit dit dah |
| W | .−− | dit dah dah |
| X | −..− | dah dit dit dah |
| Y | −.−− | dah dit dah dah |
| Z | −−.. | dah dah dit dit |
| é (accented e) | ..−.. | dit dit dah dit dit |
Figures
| Figure | Signal | Spoken |
|---|---|---|
| 1 | .−−−− | dit dah dah dah dah |
| 2 | ..−−− | dit dit dah dah dah |
| 3 | ...−− | dit dit dit dah dah |
| 4 | ....− | dit dit dit dit dah |
| 5 | ..... | dit dit dit dit dit |
| 6 | −.... | dah dit dit dit dit |
| 7 | −−... | dah dah dit dit dit |
| 8 | −−−.. | dah dah dah dit dit |
| 9 | −−−−. | dah dah dah dah dit |
| 0 | −−−−− | dah dah dah dah dah |
Punctuation and signs
| Mark or sign | Signal |
|---|---|
| Full stop (period) | .−.−.− |
| Comma | −−..−− |
| Colon or division sign | −−−... |
| Question mark (request for repetition) | ..−−.. |
| Apostrophe | .−−−−. |
| Hyphen, dash, or subtraction sign | −....− |
| Fraction bar or division sign | −..−. |
| Left-hand bracket (parenthesis) | −.−−. |
| Right-hand bracket (parenthesis) | −.−−.− |
| Inverted commas (quotation marks) | .−..−. |
| Double hyphen | −...− |
| Commercial at (@) | .−−.−. |
| Cross or addition sign | .−.−. |
| Multiplication sign | −..− |
Procedure signals (prosigns)
| Procedure signal | Signal |
|---|---|
| Understood | ...−. |
| Error (eight dots) | ........ |
| Invitation to transmit | −.− |
| Wait | .−... |
| End of work | ...−.− |
| Starting signal (before every transmission) | −.−.− |
Source: ITU-R M.1677-1, section 1.1.3 (punctuation marks and miscellaneous signs).
Using the guide
- Learn the signal for each letter by its sound. “dit” is a dot and “dah” is a dash. These spoken names are common practice, not part of the standard.
- When sending, keep the spacing rules: one dot between signals in a letter, three between letters, and seven between words.
- A dash is always three times the length of a dot, so the same sound pattern is sent at a steady rhythm.
Frequently asked questions
What is Morse code?
Morse code is a system of short signals (dots) and long signals (dashes) that stand for letters, figures, and signs. The international version is set out in ITU-R M.1677-1.
Source: ITU-R M.1677-1 (10/2009), section 1.
How long is a dash compared with a dot?
A dash is three times as long as a dot. The space between the dots and dashes of one letter is one dot long. The space between two letters is three dots long, and the space between two words is seven dots long.
Source: ITU-R M.1677-1, section 2.1 to 2.4.
What does the error signal mean?
The error signal is eight dots (........). The recommendation lists it among the miscellaneous signs, next to the procedure signals in this guide.
Source: ITU-R M.1677-1, section 1.1.3 (miscellaneous signs).
Are accented letters part of the standard?
Yes. The recommendation lists an accented E (é) with the signal ..−.. . It is listed separately from the plain letters.
Source: ITU-R M.1677-1, section 1.1.1 (letters, accented e).
Is there a single code for SOS?
The recommendation does not list SOS as a single signal. Its letters are S (...), O (−−−), and S (...), using the signals in the letter table.
Source: ITU-R M.1677-1, section 1.1.1 (letters S and O).