Morse Code Translator

How to use the Morse code translator

Morse code writes each letter, number and punctuation mark as a short pattern of dots (short signals) and dashes (long ones). This translator works both ways in one box: it is a text to Morse code converter and a Morse code decoder that turns Morse code to text.

1. Type or paste text or Morse code into the box. The translator detects which one it is and shows the translation as you type.
2. Check the result and the letter-by-letter breakdown. Characters with no Morse code are marked, and every substitution comes with a note.
3. Press Play to hear it. Set the speed in words per minute, add Farnsworth spacing if you are learning, and change the tone or volume.
4. Copy the result, share it, or download it as a WAV sound file.

The translator reads the input as Morse code when it contains only dots, dashes, spaces, slashes and vertical bars, and as text otherwise. If you want to translate a line of dots as punctuation instead, choose Text → Morse above the box. You can paste Morse written with middle dots (·), bullets, en dashes, em dashes or underscores; they are read as dots and dashes. Line breaks are kept in both directions, and Swap turns the result into the new input.

Morse code has no capital or small letters, so text comes back in capitals. Type a prosign, a group of letters sent as one character, between angle brackets: <SOS>, <AR> or <SK>. Characters that have no Morse code, such as an emoji or a ~, are never silently dropped: the breakdown marks them, a line under the result lists them, and the Characters with no Morse code option either skips them or keeps them as typed.

The Morse code alphabet

The code used for radio and international telegraphy today is International Morse code, defined by the International Telecommunication Union in Recommendation ITU-R M.1677-1. It has 26 letters plus an accented E (é), the ten figures, and a set of punctuation marks and service signals. The Chart tab of the tool above plays every one of them and prints on one page.

The numbers follow a pattern that is easy to learn: 1 to 5 start with dots and fill up with dashes, 6 to 0 start with dashes and fill up with dots. The ITU’s punctuation marks and signs, with the names the Recommendation gives them:

Some characters people often type are not in the ITU Recommendation but are widely used, mostly in amateur radio and in other languages. The translator includes them by default and labels them as extras; choose ITU-R M.1677-1 only under Translation options to leave them out.

Morse code timing: dots, dashes and gaps

Morse code is a rhythm, not just a pattern, and Recommendation ITU-R M.1677-1 fixes that rhythm in four rules, all measured in the length of one dot, called a unit:

• A dash is equal to three dots.
• The space between the dots and dashes of one letter is one dot.
• The space between two letters is three dots.
• The space between two words is seven dots.

Speed is counted in words per minute (WPM) using a standard word, PARIS. With its letter gaps and the gap after it, PARIS is exactly 50 units long (P is 11 units, A 5, R 7, I 3 and S 5, plus four letter gaps of 3 and a word gap of 7). Sending it 20 times in a minute is 20 WPM. That gives the formula the translator uses for every sound it makes:

unit (one dot) = 60,000 ms ÷ (50 × WPM) = 1,200 ms ÷ WPM

dash         = 3 units
letter gap   = 3 units
word gap     = 7 units

Because the length of a dot is the only thing that changes, the slider in the tool changes the whole rhythm in proportion. Real messages contain longer and shorter words than PARIS, so the time shown next to the result is calculated from the actual dots, dashes and gaps of your text.

Farnsworth spacing

At slow speeds a learner can count the dots of each letter, a habit that stops working as the speed rises; the ARRL’s timing standard blames it for the often-mentioned “13-WPM barrier”. Farnsworth timing avoids it: each character is sent at a real speed, say 20 WPM, and the extra time needed for a slower overall speed goes into the gaps between characters and words. The ARRL published the formula that this translator uses in 1990, for a character speed c and an overall speed s in WPM:

ta = (60 × c − 37.2 × s) ÷ (s × c)    seconds added to each 50-unit word
letter gap = 3 × ta ÷ 19
word gap   = 7 × ta ÷ 19

The 37.2 is the 31 units of dots, dashes and gaps inside PARIS at 1.2 ÷ c seconds each; the 19 is four letter gaps of 3 units plus one word gap of 7, so the added time keeps the usual 3 to 7 ratio. For characters at 20 WPM and an overall speed of 10 WPM: ta = (1,200 − 372) ÷ 200 = 4.14 seconds, so each letter gap lasts 654 ms and each word gap 1,525 ms instead of 180 ms and 420 ms, while every dot stays 60 ms long. The 1990 ARRL standard itself sends characters at 18 WPM whenever the overall speed is below 18:

Turn on Farnsworth spacing under Sound and light, pick the character speed with the Speed slider and the overall speed with the second slider. The WAV download uses the same timing.

Worked examples

Each row shows a phrase in Morse code, its length in units and how long it takes to send at 20 WPM, where one unit is 60 ms. A word gap counts 7 units, so short phrases with several words take longer than their letters suggest.

Take HELLO: H is four dots (7 units with the three gaps inside it), E one dot (1), each L is .-.. (9), and O is three dashes (11). That is 37 units of letters plus four letter gaps of 3 units, 49 units in all, or 2.94 seconds at 20 WPM.

SOS and prosigns

SOS, the international distress signal of the radiotelegraph era, is three dots, three dashes and three dots. It is sent as a single character, ...---..., with no letter gaps, which is why it is written with a bar over the letters: SOS. The International Maritime Organization points out that, contrary to popular myth, the letters do not stand for “Save Our Souls”: they have no special meaning, except that the pattern is easy to remember and to send. SOS became the worldwide distress signal through the international radiotelegraph conferences of the early 1900s.

Other signals that are sent as one character are called prosigns and are also written with a bar. Recommendation ITU-R M.1677-1 defines several of them for operating procedure, even though they have no written character of their own:

When the translator decodes one of these patterns it writes the prosign in angle brackets, such as <SK>, and shows it with a bar in the breakdown. Where a prosign is also a written sign, the sign wins: .-.-. becomes + and -...- becomes =. The ITU’s rules for a message use them: a telegram ends with the cross signal (.-.-.), a transmission ends with the cross followed by K, and the end of work is ...-.-.

Signs that Morse code does not have

Recommendation ITU-R M.1677-1 also says how to send some signs that have no Morse code of their own, and the translator follows it, with a note in the breakdown each time:

• Multiplication sign (×) is sent as the letter X.
• Percent (%) and per mille (‰) are sent as 0/0 and 0/00. A number before them is joined with a hyphen: for 2% the Recommendation says to send 2-0/0, not 20/0.
• Minutes and seconds (′ and ″) after figures are sent as one or two apostrophes, so 1′15″ becomes 1'15''.
• Curly quotes and long dashes are sent as the ITU quotation marks and hyphen.

Letters with accents that have no code in the chosen character set, such as ô or ł, are sent as the plain letter and marked “sent as O”. Anything else without a Morse code, from emoji to the tilde, is marked as missing rather than replaced by something that looks right but means something else. In the other direction, a group of dots and dashes that is not in the chart, such as ten dots, is marked as not in the chart and either skipped or kept in square brackets.

Sound, light and WAV

Press Play and the translator sends the message as a pure tone, 600 Hz by default, through the Web Audio API built into your browser. Each tone fades in and out over 5 ms so it does not click, the letter being sent lights up in the breakdown, and Pause and Stop work at any point. Tone and volume change while it plays; changing the speed stops playback, so the next Play uses the new timing. In the Chart tab, every character plays on its own.

Download WAV writes the same sound, with the same speed and Farnsworth timing, as an uncompressed WAV file (16-bit mono at 22,050 Hz) generated in your browser. WAV is the plain wrapper for uncompressed audio that the Library of Congress lists among its preferred formats for sound, and it opens in any audio player or editor. Files are limited to 10 minutes of Morse code.

Flash a light shows the code as a lamp that turns on for every dot and dash. Morse code changes several times a second, more often than the three flashes per second that the Web Content Accessibility Guidelines treat as safe for people with photosensitive epilepsy, so the light is off until you turn it on, it never fills the screen, and Gentle light, on by default, keeps the change in brightness below the guidelines’ definition of a flash. If your device asks for reduced motion, Gentle light stays on.

Tap to key: sending by hand

The Tap to key tab turns your screen into a straight key. Hold it briefly for a dot or about three times as long for a dash, with your mouse, a finger or the Space bar, and it decodes your timing: a press shorter than two units is a dot, a pause of two units ends the letter and a pause of five units starts a new word. Those thresholds sit halfway between the ITU lengths of 1 and 3 units and of 3 and 7 units, and the unit adapts to your speed as you send. If holding a key is hard, the Dot, Dash, End letter and Space buttons do the same without timing.

A short history of Morse code

Samuel F. B. Morse began working on an electric telegraph in the 1830s; the Library of Congress holds an early version of his code from about 1837. His first scheme sent numbers that had to be looked up in a code book. The dot-and-dash alphabet emerged from his collaboration with Alfred Vail, whom the Smithsonian Institution Archives credits with developing a simpler alphabetic code that made messages far quicker to read.

On February 23, 1843 the House of Representatives passed, by 89 votes to 83, the bill that gave Morse $30,000 for an experimental line from Washington to Baltimore. On May 24, 1844, in the Supreme Court room of the U.S. Capitol, Morse sent its first message to Vail in Baltimore: “What hath God wrought?”, a verse from the Book of Numbers suggested by Annie Ellsworth. The receiving apparatus embossed the dots and dashes on a paper tape that the Library of Congress still holds.

American Morse and International Morse

The code of 1844 became known as American Morse. It had spaces inside some letters and dashes of more than one length. The Library of Congress describes how it was later slightly altered to form International Morse code, which has a single dash length and no gaps inside a letter. When twenty mostly European countries founded what became the International Telecommunication Union at the 1865 International Telegraph Conference in Paris, its regulations required the adoption of Morse code and its instruments. International Morse is the code radio adopted and the one this translator uses.

From the high seas to the hobby

Radio carried Morse code to sea, and ships fitted with radiotelegraph equipment had to carry a radio officer trained in it. The Global Maritime Distress and Safety System, introduced through amendments to the SOLAS convention adopted in 1988, became fully operational on 1 February 1999, and on that date Morse code was phased out of the international distress system at sea. In the United States the FCC removed the Morse code examination from amateur radio licensing with effect from February 23, 2007. The code itself is still maintained: the ITU revised its Recommendation in 2009, noting that versions of the code have been in use since 1844 and that it continues to be used in the amateur and amateur-satellite services.

How to learn Morse code

• Learn the sound, not the picture. In his 1936 study of radio operator training, the psychologist Ludwig Koch found that people learn fastest when they hear each character as a whole sound pattern. Below about 10 WPM the pattern falls apart into separate dots and dashes, so he recommended starting at about 12 WPM.
• Add one character at a time. Koch started with two characters that sound very different and added the next only when about 90 percent were copied correctly. The chart tab lets you play any character as often as you like.
• Use Farnsworth spacing to keep characters fast while you still need time to think between them, then shrink the gaps as you improve.
• Practice little and often. Short daily sessions work better than long ones. Copy a few words, then send them back with the Tap to key pad.

Private by design

• Nothing is uploaded. Translation, sound and the WAV file are all made in your browser. The page’s Content-Security-Policy allows connections only back to this site, and the translator makes none.
• Your text is not stored. Only your settings, such as speed, tone and separators, are kept in your browser’s local storage under one key.
• No account and no cookies. Once the page has loaded, the translator works offline.

Sources

• ITU, Recommendation ITU-R M.1677-1 (10/2009): International Morse code: every character, the timing rules and the rules for ×, %, ′ and ″.
• Bloom J, ARRL Laboratory (1990). A Standard for Morse Timing Using the Farnsworth Technique. QEX, April 1990, pp. 8–9: the PARIS standard and the Farnsworth formulas.
• International Maritime Organization (1999). Shipping Emergencies: Search and Rescue and the GMDSS: SOS and the end of Morse code in the maritime distress system.
• ITU History Portal: The 1865 International Telegraph Conference.
• Library of Congress, Samuel F. B. Morse Papers: Invention of the Telegraph and Today in History, May 24: What Hath God Wrought?
• Smithsonian Institution Archives: A Forgotten History, Alfred Vail and Samuel Morse.
• Federal Register 72 FR 3081 (January 24, 2007), Amateur Service Rules, FCC 06-178: the end of the Morse code examination, effective February 23, 2007.
• Executive summary of Koch L (1936), a study of learning to receive Morse code, published by a Morse code teaching club.
• Library of Congress, Sustainability of Digital Formats: WAVE Audio File Format.
• W3C, Web Content Accessibility Guidelines (WCAG) 2.2, Success Criterion 2.3.1 Three Flashes or Below Threshold, and W3C, Web Audio API 1.1.

Reviewed by microplugins · Last updated October 2026