How to write Morse code in text: dots, dashes, spaces and slashes
To write Morse code in text, use a period for every dit and a hyphen for every dah, put one space between characters and a slash between words. HELLO WORLD comes out as .... . .-.. .-.. --- / .-- --- .-. .-.. -... A prosign, two or more letters sent as one character, is written as a single group with no spaces inside it, and named in angle brackets: <AR> is .-.-..
That is the whole convention. It is worth following exactly, because written Morse has no sound to fall back on. The spaces are the only thing that tells a reader where one letter ends and the next begins.
The rules in one table
| What you are writing | How to write it | Example |
|---|---|---|
| A dit | a period | E is . |
| A dah | a hyphen | T is - |
| The gap inside a character | nothing: the marks touch | A is .- |
| The gap between characters | one space | AN is .- -. |
| The gap between words | a slash, with a space each side | NO GO is -. --- / --. --- |
| A prosign | one group, no spaces | AR is .-.-. |
Each rule is the written form of a timing rule. In sound, the silence inside a character lasts 1 unit, the silence between characters 3 units and the silence between words 7 units. Paper cannot hold a silence, so the three gaps become nothing, a space and a slash. If you know how Morse sounds, you already know how to write it; Morse code timing: the 1, 3, 7 rule sets out the sound side.
When you write by hand, the same rules apply with a pencil: make each dash clearly longer than a dot, leave a visible space between letters, and draw a slash between words. A dash that shrinks to a dot is the usual way handwritten Morse goes wrong.
Why the spaces carry the message
Take these four marks with no spaces: .--.. Written as one group, they are P. But the same marks split differently give other letters:
| Written as | Reads as |
|---|---|
.--. |
P |
.- -. |
AN |
.-- . |
WE |
.- - . |
ATE |
. -- . |
EME |
All five are correct Morse. Only the spaces decide which one the writer meant. A run of dots and dashes with no spaces is a puzzle with several right answers, and a reader can only guess from context.
So a few habits are worth keeping:
- One space between characters, every time. Do not add a second space for emphasis. Some readers and tools treat a wide gap as a word break.
- A slash with a space on each side.
.- / -.is easier for a person to read than.-/-., and it leaves no doubt that the slash is not part of a character. - Never break a character across two lines. If a line runs out, move the whole character down.
- Punctuation is its own character. A full stop at the end of a sentence is
.-.-.-, written as a separate group. It is not an extra period stuck on the last letter. HI followed by a full stop is.... .. .-.-.-, not.... ..., which would read as HS.
That last mistake is easy to make, because a dit and a full stop are drawn with the same mark. In written Morse, every period belongs to a dit, never to the sentence.
Writing prosigns
A prosign is sent as one character, with no letter gap between its letters, so in code it is written as one group: AR is .-.-., SK is ...-.- and BT is -...-. To name a prosign in ordinary text, write its letters with a bar over them, or, since a bar is awkward to type, in angle brackets: <AR>, <SK>, <BT>.
The best known prosign is SOS. Sent correctly it is one continuous character, ...---..., nine elements with no letter gaps. You will often see it written ... --- ..., as three letters, and a reader will understand it either way on paper. In sound, only the first is the distress signal.
Several prosigns share their code with a punctuation mark. AR is the same as plus, BT the same as equals, KN the same as an open parenthesis. On paper, .-.-. alone could be either, and only context tells the reader which. If your message needs a prosign, name it in brackets beside the code, so nobody reads a plus sign. Morse code prosigns explained covers what each one means.
Other notations you will meet
The period and hyphen convention is the common one, but older books, puzzles and websites use others. Most of them can be converted back with a find and replace in a text editor.
- A middle dot or a bullet for a dit. It reads clearly in print and looks like a dot should. Replace it with a period before you paste the text anywhere that expects the usual form.
- An underscore for a dah. A becomes
._and B_.... Some people like it because an underscore looks longer than a hyphen. - An en dash or an em dash for a dah. Usually nobody chose this: an editor turned two hyphens into a dash on its own. One long dash where there should be two dahs changes the letter, so this is the one to watch for.
- Other word separators. A vertical bar,
|, three spaces, or one word per line. - Rhythm words. Learners often write the sound instead of the picture: A is di-dah, B is dah-di-di-dit. A dit inside a letter is “di”, a final one “dit”. It is a good way to note letters while you learn them by ear, since it describes what you hear.
One more variant matters if you read old telegraph material. American Morse, the landline code of the railroads, has spaces inside some characters, so its written form does not follow these rules at all. Everything here is International Morse, the code used on radio and taught today; American Morse code vs International Morse code explains the difference.
Typing Morse on a Mac without it changing
Software that “improves” your punctuation can break written Morse without telling you.
- Smart dashes. In many Mac apps, two hyphens typed together become a dash. To change the setting for your Mac, open System Settings, Keyboard; under Text Input, click Edit next to Input Sources; select All Input Sources; turn off “Use smart quotes and dashes”; click Done. In many apps you can also switch it off for the app you are in with Edit, Substitutions, Smart Dashes.
- Ellipses. Some editors replace three periods with a single ellipsis character. S is
..., so every S in a message can turn into one character that no decoder reads as Morse. - Fonts. In some fonts a period and a hyphen are hard to tell apart at a glance. A monospaced font, where every mark takes the same width, makes groups easier to count when you check a message by eye.
If you paste Morse from one place to another and it stops decoding, look for a long dash or an ellipsis character first. How to copy and paste Morse code so it reads right goes through the rest.
On a Mac, Dot & Dash reads this notation in its Transcribe screen. Morse to Text takes “Dots and dashes, characters split by spaces, words by /”, and it also accepts a middle dot or a bullet for a dit, an underscore or an en dash for a dah, and splits words at a vertical bar, three or more spaces, or a new line. Text to Morse goes the other way, giving you a message’s Morse ready to copy, and reads <AR>, <BT>, <SK> and <HH> in angle brackets as prosigns.
Questions
Do you put spaces between the dots and dashes of one letter?
No. The marks of one character touch, like .- for A. A space inside a character splits it in two, so . - reads as E and T, not A.
Do you need spaces around the slash between words?
The slash alone marks the word break, so .-/-. is still readable. A space on each side, as in .- / -., is easier on the eye and leaves no doubt that the slash stands on its own.
How do you write a full stop in Morse code?
As its own character, .-.-.-, with a space before it like any other character. Do not add a plain period to the last letter, because a reader will take it as one more dit.
How do you write SOS in Morse code?
As one group, ...---..., because SOS is a prosign sent as a single character. Written as three letters, ... --- ..., it is still understood on paper, but sent with letter gaps it is the letters S, O and S, not the signal.