Morse code numbers 0 to 9, and the pattern behind them
Morse code numbers all have exactly five elements, and they follow one simple pattern. From 1 to 5, the figure tells you how many dits come first, and dahs fill the rest: 1 is .----, 2 is ..---, and 5 is five dits, ...... From 6 to 0 the dahs come first instead: 6 is -...., 7 is --..., and 0 is five dahs, -----. Learn that rule and you can work out any figure without a chart.
The ten figures
| Figure | Code | Rhythm | How it is built |
|---|---|---|---|
| 1 | .---- |
di-dah-dah-dah-dah | 1 dit, then dahs |
| 2 | ..--- |
di-di-dah-dah-dah | 2 dits, then dahs |
| 3 | ...-- |
di-di-di-dah-dah | 3 dits, then dahs |
| 4 | ....- |
di-di-di-di-dah | 4 dits, then a dah |
| 5 | ..... |
di-di-di-di-dit | 5 dits |
| 6 | -.... |
dah-di-di-di-dit | 1 dah, then dits |
| 7 | --... |
dah-dah-di-di-dit | 2 dahs, then dits |
| 8 | ---.. |
dah-dah-dah-di-dit | 3 dahs, then dits |
| 9 | ----. |
dah-dah-dah-dah-dit | 4 dahs, then a dit |
| 0 | ----- |
dah-dah-dah-dah-dah | 5 dahs |
Every letter of the alphabet has four elements or fewer, so a five-element pattern is never a letter. That is a useful check when you are decoding by hand.
The pattern, three ways to see it
Counting from the front. For 1 to 5, count the dits at the start. For 6 to 9, count the dahs at the start and add five: 6 has one dah, 9 has four. Zero sits at the end of the run as if it were ten, with five dahs.
Opposites. Swap every dit and dah in a figure and you get the figure five places away: 1 and 6, 2 and 7, 3 and 8, 4 and 9, 5 and 0. So ..--- (2) turned inside out is --... (7).
Mirrors. Read a figure backward and you get the one that adds up to ten with it: 1 and 9, 2 and 8, 3 and 7, 4 and 6. So 3, ...--, read right to left is --..., which is 7. The figures 5 and 0 read the same both ways.
These are handy for writing and decoding, and for checking a number you are about to engrave or tattoo. They are less useful when you listen, which is the next point.
Hearing figures without counting
Five elements is a lot to count, and counting is slow. Instead, listen for two things: how the figure starts, and where it turns.
- A figure that starts with a dit is 1 to 5. A figure that starts with a dah is 6 to 0.
- Each figure turns once. In 3, the sound switches from dits to dahs after the third element; in 8, from dahs to dits after the third. The point where the rhythm changes is the figure, and with practice you hear that turn as a shape rather than a position.
- 5 and 0 never turn. They are an unbroken run of dits or dahs, which makes them the easiest two to recognize.
Some figures sit one element away from a letter, and they get confused early on:
| Figure | Code | Letter | Code |
|---|---|---|---|
| 1 | .---- |
J | .--- |
| 4 | ....- |
V | ...- |
| 5 | ..... |
H | .... |
| 6 | -.... |
B | -... |
| 7 | --... |
Z | --.. |
In each pair the figure is the longer one: one more dit or dah than the letter. If they blur for you, practice the pairs side by side by ear until the extra element jumps out. Zero and O are a looser pair: both are all dahs, five against three.
Why numbers are slow to send
Because every figure has five elements, figures take far longer than most letters. Counting units (a dit is 1, a dah is 3, and each gap inside a character is 1):
| Figure | Units | At 20 WPM |
|---|---|---|
| 5 | 9 | 540 ms |
| 4 or 6 | 11 | 660 ms |
| 3 or 7 | 13 | 780 ms |
| 2 or 8 | 15 | 900 ms |
| 1 or 9 | 17 | 1020 ms |
| 0 | 19 | 1140 ms |
E takes 1 unit and T takes 3, so a single zero takes nineteen times as long as an E. A string of figures, such as a long serial number, eats time quickly. How long is a dit shows how to turn units into milliseconds at any speed.
Cut numbers
That cost is why radio operators, contest operators especially, often shorten figures where everyone expects a number. In these “cut numbers” N, -., stands for 9, and T, -, stands for 0. A for 1 is also common. The best-known example is the signal report 599, which is very often sent as 5NN: ..... -. -. instead of ..... ----. ----., which is 25 units instead of 49.
Cut numbers only work when the receiver knows a number is coming, as in a signal report or a contest exchange. Everywhere else, send figures in full. RST and 5NN signal reports covers what the three digits of 599 mean.
Writing numbers in Morse
Send a number one figure at a time, with a normal three-unit gap between figures, exactly as you would between letters. The year 1906 is:
.---- ----. ----- -....
Where a number is written with a slash, as in a fraction or a date, send the slash, -..-., between the parts. Figures also turn up inside words on the air: every amateur callsign has a figure in it, as in K1ABC (a made-up example), and 73, --... ...--, means best regards. How to send and copy callsigns deals with the letter and figure mix in callsigns.
Learning the figures
Whether you meet the figures after the letters or mixed in with them, the pattern makes them quick to pick up. Still, learn them the same way as letters: by sound, at a real character speed, with the pattern as a backup for when you are unsure rather than as the way you read them.
Everyday numbers make good practice material without any equipment. Say the time in rhythm words when you look at a clock, or sound out a house number or a date as you pass it. It feels silly at first, and it keeps the figures fresh between practice sessions.
In Dot & Dash, the figures come in chapters 13 to 16 of the course (1, 2 and 3, then 4, 5 and 6, then 7 and 8, then 9 and 0), and once the first figures are learned, Practice adds drills on made-up callsigns, which mix letters and figures the way real ones do.
Questions
Why do all Morse code numbers have five elements?
Every figure is five elements, so the ten form one regular family you can work out from a single rule, and none of them can be mistaken for a letter, since no letter has more than four elements.
What is zero in Morse code?
Zero is five dahs, -----, dah-dah-dah-dah-dah. In cut numbers it is often shortened to T, a single dah, when a number is expected.
What does 5NN mean in Morse code?
It is the signal report 599 sent with cut numbers, where N stands for 9. It means readability 5, strength 9 and tone 9, the top report.
Is the figure 1 the same as the letter J?
No. J is .---, one dit and three dahs, while 1 is .----, one dit and four dahs. The extra dah is the whole difference, so it is worth practicing the two by ear.