# Morse code: why E is a single dot and Q takes four signs

> Morse code looks like random dots and dashes, but it is a carefully designed compression scheme: common letters get short codes, rare letters get long ones. This guide shows the timing rules, the maths of why it works, and how fast operators really send.

Published 2026-10-08 by Toolcloak. 4 minute read. Original: https://toolcloak.pages.dev/articles/morse-code-why-e-is-one-dot-and-q-is-four-signs-long
Related free tool: [Morse Code Translator](https://toolcloak.pages.dev/tools/morse-code-translator)

Every letter of the alphabet can be sent down a wire using just two signals: a short one (dot) and a long one (dash). Morse code was built for the telegraph in the 1800s and is still used by radio amateurs, pilots checking a beacon and people who like puzzles. What makes it clever is not the dots and dashes. It is the order in which the codes were handed out.

> **In short**
> - A **dash lasts 3 dots**. The gap between signs is 1 dot, between letters 3 dots and between words 7 dots.
> - Common letters get short codes: **E is one dot, T is one dash**. Rare ones are long: Q is `--.-`.
> - That design makes average English about **19% shorter** to send than if the same codes were handed out in alphabetical order.
> - **SOS** is `... --- ...`: 27 dot-lengths of signal. It does not stand for any words.

## The whole alphabet

International Morse code has 26 letters, 10 digits and a handful of punctuation marks. Here are all the letters. Look for the pattern: the shortest codes belong to letters you meet all the time.

| Letter | Code | Letter | Code | Letter | Code |
| --- | --- | --- | --- | --- | --- |
| A | .- | B | -... | C | -.-. |
| D | -.. | E | . | F | ..-. |
| G | --. | H | .... | I | .. |
| J | .--- | K | -.- | L | .-.. |
| M | -- | N | -. | O | --- |
| P | .--. | Q | --.- | R | .-. |
| S | ... | T | - | U | ..- |
| V | ...- | W | .-- | X | -..- |
| Y | -.-- | Z | --.. |  |  |

*Dot is a short signal, dash a long one. Digits are always five signs: 1 is `.----`, 5 is `.....` and 0 is `-----`.*

Try it: [Morse Code Translator](https://toolcloak.pages.dev/tools/morse-code-translator). Type any sentence and see it as dots and dashes, or paste Morse and read it back as text.

## Time, not symbols, is what counts

A dash is not just “a different symbol”. It is a signal held three times as long as a dot, and the silences have exact lengths too. Without them, `...---...` could not be told apart from other letter splits. All timing is counted in one basic unit, the length of a dot.

**How long each part lasts, in dot units**

|  | Units |
| --- | --- |
| Dot | 1 |
| Dash | 3 |
| Gap inside a letter | 1 |
| Gap between letters | 3 |
| Gap between words | 7 |

*Everything else follows from these five numbers. Skilled operators can hear the gaps as clearly as the signs.*

**Building SOS, piece by piece (dot units)**

| Step | Amount |
| --- | --- |
| S (. . .) | 5 |
| Letter gap | +3 |
| O (- - -) | +11 |
| Letter gap | +3 |
| S (. . .) | +5 |

*S is three dots plus two gaps: 1+1+1+1+1 = 5. O is three dashes plus two gaps: 3+1+3+1+3 = 11. Total 27 units.*

> **SOS is a pattern, not an abbreviation:** SOS was chosen as a distress signal because `... --- ...` is simple and hard to mistake, not because the letters stand for “Save Our Souls”. Operators send it as one run with no letter gaps, so it sounds like a single rhythm.

## Why common letters get short codes

Imagine a telegraph operator who has to send thousands of words a day. If the most frequent letter, E, takes 1 unit and a rare one like Q takes 13, the rare letters barely matter because they hardly appear. The result is a shorter message overall. This is the same idea behind modern file compression.

**Time to send each of the ten most common letters (dot units)**

|  | Value |
| --- | --- |
| E | 1 |
| T | 3 |
| A | 5 |
| O | 11 |
| I | 3 |
| N | 5 |
| S | 5 |
| H | 7 |
| R | 7 |
| D | 7 |

*E takes 1 unit, T and I take 3, A, N and S take 5. Even the longest of these, O at 11, is not long.*

**Time to send the five rarest letters (dot units)**

|  | Value |
| --- | --- |
| Q | 13 |
| J | 13 |
| X | 11 |
| Z | 11 |
| K | 9 |

*Q and J take 13 units each. They appear in about one letter in a thousand, so the cost barely adds up.*

**Average time per letter of English, by how the codes are assigned (dot units)**

|  | Units |
| --- | --- |
| Real Morse (by frequency) | 6.1 |
| Same codes, alphabetical order | 7.5 |
| Worst case: rare letters short | 10.6 |

*Weighted by typical English letter frequencies (E 12.7%, T 9.1% and so on). The same set of codes can be about 1.7 times slower if handed out the wrong way round.*

## How fast is “fast”?

Speed is measured in words per minute, using the word PARIS as the standard. PARIS plus the gap after it takes exactly 50 units, so at 1 WPM a dot lasts 1.2 seconds. The faster the speed, the shorter the unit.

**Length of one dot at each speed (milliseconds)**

|  | Value |
| --- | --- |
| 5 | 240 ms |
| 10 | 120 ms |
| 15 | 80 ms |
| 20 | 60 ms |
| 25 | 48 ms |
| 30 | 40 ms |

*Labels are words per minute. At 20 WPM a dot is 60 ms and a dash 180 ms. Beginners usually learn at 5 to 10 WPM; fast operators pass 30.*

**Sending a few real words**

|  | Value | Note |
| --- | --- | --- |
| SOS | 27 units | About 1.6 s at 20 WPM |
| HELLO | 49 units | About 2.9 s at 20 WPM |
| PARIS (standard word) | 43 + 7 | Exactly 50 with the word gap |

*Seconds are units × 0.06 at 20 WPM. Longer words take longer, but not in proportion to their letter count.*

**Reading Morse by ear, the way operators learn**

1. **Hear the rhythm, not the dots.** Learn each letter as a sound pattern. “Di-dah” is A, not “dot dash”.
2. **Listen for the gaps.** A longer pause means a new letter. A much longer pause means a new word.
3. **Copy at a comfortable speed.** Start at 15 WPM with long gaps between letters, then shrink the gaps.

## Where Morse still shows up

- **Amateur radio**: many licence holders still use it, because a narrow Morse signal can be heard when voice cannot.
- **Navigation beacons**: some radio beacons identify themselves with a short Morse code.
- **Accessibility**: some people with limited mobility can type using two switches and Morse.
- **Phones and watches**: a vibration or light flash can send a message when you cannot speak.

> **Learn it faster:** Do not memorise a chart of dots and dashes. Learn the sound of each letter at full speed and practise for ten minutes a day. Most people can read the full alphabet in a few weeks this way.

The idea of giving the shortest codes to the most common symbols is exactly what compression formats do. For a related story about encoding text, read about [Base64](https://toolcloak.pages.dev/articles/base64-is-not-encryption-and-it-makes-files-a-third-bigger), and for another simple cipher you can crack by counting letters, see the [Caesar cipher](https://toolcloak.pages.dev/articles/caesar-cipher-why-only-25-keys-means-anyone-can-crack-it).

## Frequently asked questions

### What does SOS mean in Morse code?

SOS is `... --- ...`. It is a distress signal chosen because the pattern is simple and unmistakable. It does not stand for any words.

### How long is a dash compared with a dot?

Three times as long. The gap between signs of one letter is one dot, between letters three dots and between words seven dots.

### Why is E just one dot?

E is the most common letter in English, so it was given the shortest possible code. T, the second most common, gets the single dash.

### How do you write numbers in Morse code?

Every digit is five signs long: 1 is `.----`, 2 is `..---`, 3 is `...--`, 4 is `....-`, 5 is `.....`, 6 is `-....`, 7 is `--...`, 8 is `---..`, 9 is `----.` and 0 is `-----`.

### How fast can people send Morse code?

Beginners start at 5 to 10 words per minute. Experienced operators send 20 to 30, and top competitors reach well over 40.

### Is Morse code still used?

Yes, mainly by amateur radio operators, in some navigation beacons and as an accessibility input method.