Morse code translator with sound, light and practice mode
Translate text to Morse code and back with the ITU alphabet, play it as sound, light or vibration, set Farnsworth spacing and practise copying letters.
Morse code: ITU alphabet, timing and words per minute
In Morse code a dash equals three dots; one dot of silence separates the signals of a letter, three separate letters and seven separate words (ITU-R M.1677-1). Speed is measured with the word PARIS, 50 units long: a dot lasts 1.2 ÷ speed seconds, which is 60 ms at 20 WPM.
Timing and speed
With c the character speed in words per minute, one unit lasts u = 1.2 ÷ c seconds. Farnsworth spacing keeps characters at speed c but stretches the gaps for a slower effective speed s: the total delay added to a 50-unit word is ta = (60c − 37.2s) ÷ (sc), with 3/19 of ta between letters and 7/19 between words (ARRL standard).
Example
At 20 WPM, u = 1.2 ÷ 20 = 0.06 s: a dot lasts 60 ms, a dash 180 ms, and PARIS with its final gap 50 × 0.06 = 3 s. At Farnsworth 18/5 (characters at 18, overall 5), ta = (60 × 18 − 37.2 × 5) ÷ (5 × 18) = 9.93 s, so 1.57 s between letters and 3.66 s between words; one PARIS then takes 12 s, as at 5 WPM.
Alphabet and limits
The table follows ITU-R M.1677-1: 26 letters, accented É, 10 digits and 14 signs, plus service signals. Other accented letters lose their accent, and % is sent as 0/0, as the recommendation specifies. In light mode, characters are capped at 7 WPM: a dot and its gap then last 0.34 s, which keeps flashing to 3 flashes per second, the WCAG 2.3.1 threshold. Sound starts at a low volume with 5 ms ramps that prevent clicks.
Sources and dates: ITU-R M.1677-1 (10/2009); J. Bloom, ARRL, QEX (04/1990); W3C, WCAG 2.3.1 (checked on 29/10/2026)
Frequently Asked Questions
How is Morse code speed measured?
In words per minute based on the word PARIS, which is 50 units long: one dot lasts 1.2 ÷ speed seconds. At 20 WPM a dot lasts 60 ms and a dash 180 ms; at 5 WPM a dot lasts 240 ms.
What is Farnsworth spacing?
Characters are sent fast, for example at 18 WPM, while the gaps between letters and words are stretched for a slower overall speed such as 5 WPM. You learn the sound of each letter instead of counting dots.
How do you write SOS in Morse code?
SOS is ... --- ...: three dots, three dashes, three dots. At 20 WPM the whole signal, 27 units long, lasts about 1.6 seconds.
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