Morse Code Timing
Every length in Morse code is a multiple of one time unit. Set a speed below to see exactly how long each dot, dash and gap becomes.
Morse Code Timing Calculator
| Element | Units | Length |
|---|---|---|
| Dot (dit) | 1 | 60 ms |
| Dash (dah) | 3 | 180 ms |
| Gap inside a character | 1 | 60 ms |
| Gap between characters | 3 | 180 ms |
| Gap between words | 7 | 420 ms |
| The word PARIS | 50 | 3.00 s |
The 1-3-3-7 Rule
Morse code has exactly one measurement in it: the time unit, usually called a dit. Every other length is a multiple of it, and the whole system fits into four numbers.
- 1 — a dot, and the gap between the parts of one character
- 3 — a dash
- 3 — the gap between two characters
- 7 — the gap between two words
Because everything is a ratio, changing speed is just changing the length of the unit. Nothing else about the code moves.
Why the silences matter
The gaps are not pauses between the real signal — they are part of it. Take the letters
A (.-) and N (-.). Sent correctly there are three units of
silence between them. Run them together and you get .--., which is the
letter P.
This is the most common fault in hand-sent Morse: the tones are fine but the spacing drifts, and the receiving operator reads different words than the ones being sent.
What Words Per Minute Really Measures
Morse speed is quoted in words per minute, but a “word” has to be defined or the number means nothing — some words take far longer to send than others. The standard reference is PARIS, which comes to exactly 50 time units including the word gap that follows it.
So 20 WPM means the word PARIS could be sent twenty times in a minute: 1000 units per minute, which works out at 60 milliseconds per unit. That is where the formula comes from:
one time unit in milliseconds = 1200 ÷ WPM
You will occasionally see CODEX used instead, a 60-unit reference favoured for random letter groups. A speed quoted against CODEX is about 20% slower than the same number against PARIS, which is worth knowing if two sources disagree.
Farnsworth timing
There is one common and deliberate exception to the rules above. In Farnsworth timing the characters are sent at a fast speed — say 18 WPM — but the gaps between them are stretched so the overall rate comes out at perhaps 8 WPM.
The point is that a learner hears each character at its true rhythm from the start, rather than as a slow row of separate beeps, while still getting thinking time in between. The practice trainer is built on the same principle: the characters stay quick and the space between them is where you catch up.
To hear the difference for yourself, change the speed slider on the Morse code audio page and listen to the same message at 10 and at 25 WPM.
Frequently Asked Questions
How long is a dot in Morse code?
One time unit, and the time unit depends on the speed. The formula is 1200 divided by the speed in words per minute, in milliseconds — so at 20 WPM a dot is 60 ms, and at 10 WPM it is 120 ms.
How much longer is a dash than a dot?
Exactly three times. If a dot is 60 milliseconds then a dash is 180. Because it is a ratio rather than a fixed length, the code sounds correct at every speed.
What is the 1-3-3-7 rule in Morse code?
It is the whole timing system in four numbers: a dot is 1 unit, a dash is 3, the gap between the parts of one character is 1, the gap between characters is 3, and the gap between words is 7.
What does words per minute mean in Morse code?
It is measured against the reference word PARIS, which is exactly 50 time units long including the word gap that follows it. Sending PARIS twenty times in a minute is 20 WPM.
Why is PARIS used as the reference word?
Because its mix of dots, dashes and gaps comes out at 50 units, close to the average for ordinary English text. That makes it a fair yardstick, which a word made only of short or only of long characters would not be.
What is Farnsworth timing?
Sending the characters themselves at a fast speed but leaving extra space between them. It lets a learner hear each character at its real rhythm while still having thinking time, which avoids the habit of counting individual dots.
How do I calculate Morse code timing?
Start with the time unit: 1200 divided by the speed in WPM gives milliseconds. Then multiply by 1 for a dot, 3 for a dash, 1 for the gap inside a character, 3 for the gap between characters and 7 for the gap between words. The calculator above does it for you.
Does the gap between letters really matter?
Yes, it carries as much meaning as the tones. Run the letters A and N together without the three-unit gap and .- -. becomes .--., which is the letter P.