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Morse Code Guide
ITU Standard Explainer

Morse Code Timing Explained: Dots, Dashes, and the Gaps That Make It Work

Every Morse character is built from two signals and three silences. Get the signals right and you have dots and dashes. Get the silences wrong and the message becomes noise.

ITU-R M.1677-1 standardInteractive WPM calculatorLive waveform diagram~7 min read

01One Unit Governs Everything

The ITU does not define Morse timing in fixed milliseconds. It defines timing in relative units. The base unit is the duration of one dot, and every dash or gap is a multiple of that unit.

Change the speed and all values scale together. That is why slow hand-key Morse and fast electronic keyers still produce the same recognizable code shape.

The PARIS reference word: PARIS encodes to exactly 50 units. At 20 WPM, one unit is 1200 / 20 = 60 ms.

02Signals and Silences: The Complete Rule Set

Morse has exactly two signal types and three silence types. Together they form an unambiguous message when each ratio is respected.

.Dot (dit)
1 unit - signal on

The shortest signal and the base unit. The letter E is a single dot.

-Dash (dah)
3 units - signal on

Exactly three times a dot. The letter T is a single dash.

[ ]Symbol gap
1 unit - signal off

The silence between dots and dashes inside a single letter.

[ ... ]Letter gap
3 units - signal off

The silence between two letters inside the same word.

[ / ]Word gap
7 units - signal off

The longest defined pause, used between two words.

WPMSpeed
PARIS = 50 units

Words per minute is measured against the standard word PARIS.

Easy symmetry: Dash = letter gap = 3 units. Dot = symbol gap = 1 unit. Word gap = 7 units.

03Every Timing Value at Your Chosen Speed

Drag the slider to your target WPM. These are the exact millisecond values a timing-aware Morse keyer should use.

Live calculatorITU timing calculator
Speed20 WPM
60 ms
1 unit
base duration
60 ms
dot
1 unit
180 ms
dash
3 units
60 ms
symbol gap
1 unit
180 ms
letter gap
3 units
420 ms
word gap
7 units

Formula: 1 unit = 1200 / WPM ms. Reference word PARIS = 50 units.

04What SOS Looks Like as a Timing Diagram

SOS is three dots, three dashes, and three dots. The widths below are proportional to timing units, so the ratios stay accurate at every speed.

Signal waveform: SOS at 20 WPM, 1 unit = 60 ms
DotDashSymbol gapLetter gap
3u
3u
3u
3u
3u
S (...)O (---)S (...)

05Why Timing-Aware Tools Matter

Static text tools can display Morse patterns, but they cannot tell whether your timing was correct. A keyer measures real press and release durations.

Static text input

x Timing is fabricated by playback

x Letter gaps are inferred from spaces

x Word gaps require typed slashes

x No timing feedback

Mouse-click keyer

+ Press duration is measured

+ Letter gaps come from release pauses

+ Word gaps emerge from 7-unit silence

+ Builds real keying accuracy

Critical distinction: A static text tool simulates Morse output. A keyer implements Morse input.

06Frequently Asked Questions About Timing

What are the official Morse code timing rules?

The ITU-R M.1677-1 standard defines dot as 1 unit, dash as 3 units, symbol gap as 1 unit, letter gap as 3 units, and word gap as 7 units. The actual milliseconds are set by WPM.

What is the letter gap vs. word gap?

A letter gap is 3 units of silence between letters in the same word. A word gap is 7 units of silence between words.

How does Morse code WPM work?

WPM uses the reference word PARIS because it totals 50 timing units. The formula for one unit is 1200 divided by WPM milliseconds.

What is dit dah spacing?

Dit-dah spacing is the 1-unit silence between symbols inside a letter. For A, the dot and dash are separated by one dot-length of silence.

Why does timing matter for beginners?

Correct patterns are only half of Morse code. The gaps tell listeners where letters and words begin and end, so bad timing can make correct symbols unreadable.

What speed should beginners start with?

Many beginners start around 5 WPM for deliberate practice. Koch and Farnsworth methods often keep character rhythm faster while increasing spacing for easier processing.

Timing rules follow ITU-R M.1677-1. WPM formula: 1 unit = 1200 / WPM ms, based on the PARIS reference word.