Morse Code - History, Chart and How to Read

Morse Code

What is Morse Code?

Morse code is a method of transmitting telegraphic information, using standardized sequences of short and long elements to represent the letters, numerals, punctuation and special characters of a message.

The short and long elements can be formed by sounds, marks or pulses, in on off-keying, and are commonly known as "dots" and "dashes" or "dits" and "dahs". If you need a list of the alphabet in Morse code please click on the image to the left.

The History of Morse Code

Originally created for Samuel F. B. Morse's electric telegraph in the early 1840s, Morse code was also extensively used for early radio communication, beginning in the 1890s.

For the first half of the twentieth century, the majority of high-speed international communication was conducted in Morse code, using telegraph lines, undersea cables, and radio circuits. However, the variable length of the Morse code characters made it hard to adapt to automated circuits, so for most electronic communication it has been replaced by more machinable formats, such as Baudot code and ASCII.

How is Morse Code Used Today?

The most popular current use of Morse code is by amateur radio operators. Although no longer a requirement for Amateur licensing in most countries, it also continues to be used for specialized purposes, including identification of navigational radio beacon and land mobile transmitters, plus some military communication, including flashing-light semaphore communications between ships in some naval services.

Morse code is the only digital modulation mode designed to be easily read by humans without a computer, making it appropriate for sending automated digital data in voice channels, as well as making it ideal for emergency signalling, such as by way of improvised energy sources that can be easily "keyed", for example by supplying and removing electric power (e.g. by switching a breaker on and off).

Because it is not as well-known as it once was, it can also be used to convey secret messages, even in plain sight. An example of this can be found in a Morse code bracelet. This can be worn and have a special meaning to the wearer or their partner, which will be unknown to everyone else who sees this if they do not know how to read and decipher Morse code!

SOS Morse Code

Help in Morse Code - What does SOS Stand For?

SOS actually did not stand for anything, orginally; "Save Our Seamen", "Save our Ship", "Survivors On Shore", "Save Our Souls" or "Save Our Selves" are just ways to guess the meaning. But in reality, it was used because the letter S and O are easy to make and are distinctive.

The letter S has a distinctive 3 dots (...) and the letter O has a distinctive 3 dashes (---). Click on the image above for a list of the rest of the Alphabet in Morse Code.

International Morse code is composed of six elements:

  • short mark, dot or 'dit' (·)
  • longer mark, dash or 'dah' (-)
  • intra-character gap (between the dots and dashes within a character)
  • short gap (between letters)
  • medium gap (between words)
  • long gap (between sentences — about seven units of time)

These six elements serve as the basis for International Morse code and therefore can be applied to the use of Morse code worldwide.

How is Morse Code Transmitted?

An old telegraph sounder used to send Morse code messages

Morse code can be transmitted in a number of ways: originally as electrical pulses along a telegraph wire, but also as an audio tone, as a radio signal with short and long pulses or tones, or as a mechanical or visual signal (e.g. a flashing light) using devices like an Aldis lamp or a heliograph.

Morse code is transmitted using just two states — on and off — so it was an early form of a digital code. However, it is technically not binary, as the pause lengths are required to decode the information.

How Long is a Dot and a Dash?

The dot/dit duration is used as the basic unit of time measurement when it comes to Morse code transmission. The duration of a dash/dah is three times that of a dot/dit. In other words, the signal for the dash/dah should be present for three times the length of time that the sender takes to make a dot/dit.

Gaps Between Letters, Words and Sentences

Of course, tapping or flashing to transmit letters is one thing, but a message will only make sense if those letters can be written as words and sentences. Otherwise, all the receiver will get is one long block of letters.

As mentioned above, there are short, medium and long gaps between different letters, words and sentences respectively.

Each dot/dit or dash/dah within a letter or number (or other character) is followed by a period of signal absence, called a space, equal to the dot/dit duration. This space tells the receiver that the Morse code for that particular character has finished, and that the next signal received will be the start of the next letter.

Why this is important? Well, using the Morse code chart above, take a look at the letters S, T and V. If there were no pauses between letters, an operator wouldn’t know whether the three dots and a dash were the letters S and T, or whether they were all part of the same letter (V, which as you can see is composed of three dots and a dash).

The letters of a word are separated by a space of duration equal to three dots/dits, and words are separated by a space equal to seven dots/dits. This enables the operator to easily distinguish between different letters and words, so that a readable message can be understood.

Morse Code Alphabet

As well as viewing the Morse code chart image above, you can also see the entire Morse code alphabet letters in the table below:

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

Morse Code Numbers

As well as viewing the Morse code chart image above, you can also see numbers represented by Morse code in the table below:

Number Morse Code Number Morse Code
1 Dot - Dash - Dash - Dash - Dash 6 Dash - Dot - Dot - Dot - Dot
2 Dot - Dot - Dash - Dash - Dash 7 Dash - Dash - Dot - Dot - Dot
3 Dot - Dot - Dot - Dash - Dash 8 Dash - Dash - Dash - Dot - Dot
4 Dot - Dot - Dot - Dot - Dash 9 Dash - Dash - Dash - Dash - Dot
5 Dot - Dot - Dot - Dot - Dot 0 Dash - Dash - Dash - Dash - Dash

Morse Code Characters and Symbols

As well as viewing the Morse code chart image above, you can also see characters and symbols represented by Morse code in the table below:

Character Morse Code Character Morse Code
Full Stop Dot - Dash - Dot - Dash - Dot - Dash Forward Slash Dash - Dot - Dot - Dash - Dot
Comma Dash - Dash - Dot - Dot - Dash - Dash @ Sign Dot - Dash - Dash - Dot - Dash - Dot
Question Mark Dot - Dot - Dash - Dash - Dot - Dot

Morse Code to English and How to Read Morse Code Quiz

Now that you have learned how to decipher and transmit Morse code from and into English, why not have a go at the questions below in order to check your understanding of how to read and write Morse code?

Also, don't forget to check out our Morse code translator page. This handy tool allows you to quickly and easily type in a sentence and convert it into Morse code.


1. What letter is represented by dash - dash - dot - dot?

2. How do you spell out the word cat in Morse code?

3. What other names are dots and dashes known by?

4. Is a short, medium or long gap used to distinguish between the end of one word and the start of another?

5. When was Morse code originally created?


  • 1. Z
  • 2. dash - dot - dash - dot [gap] dot - dash [gap] dash
  • 3. dits and dahs
  • 4. Medium
  • 5. Early 1840s

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