Morse Code Timing

Morse is a rhythm as much as a code. All lengths are multiples of one time unit, which is the length of a dot:

• Dot = 1 unit
• Dash = 3 units
• Gap inside a letter = 1 unit
• Gap between letters = 3 units
• Gap between words = 7 units

Speed is measured in words per minute using the PARIS standard. The word PARIS plus a word gap is 50 units. At 1 WPM those 50 units fill one minute, so one unit lasts 1,200 milliseconds. At 20 WPM a unit is 60 ms.

This site schedules tones with the Web Audio API from that formula, rather than a stack of timers. That keeps long messages steady when you press Play or export a WAV file.