Does morse code have spaces?

Yes, three of them, and they carry as much as the marks do. Inside a character the gap is one unit, the same length as a dit. Between characters it is three units, and between words it is seven. Change those lengths and the same marks regroup into different letters.

.... .. / - .... . .-. .

Two words, so you can hear all three gaps: the short one inside H, the longer one between letters and the long one before THERE.

Three gaps, fixed by the standard

ITU-R M.1677-1 defines silence as carefully as it defines sound. There are three lengths, measured in the same units as the marks:

One unit between the marks inside a single character, the same length as a dit
Three units between characters, the same length as a dah
Seven units between words

A unit is 1,200 milliseconds divided by the speed in words per minute (WPM), so at 20 WPM the three gaps are 60, 180 and 420 milliseconds. At 5 WPM they are 240 milliseconds, 720 milliseconds and 1.68 seconds.

Play HI THERE above and listen for all three. The four dits of H are one unit apart. The step to I is three units. The step to THERE is seven, long enough that the pause is obvious even at 20 WPM.

The gaps decide where letters begin

Marks alone are ambiguous. Four dits in a row could be H, or two Is, or four Es, and nothing about the dits themselves says which. Only the silence between them does.

That is why timing errors destroy a message so completely. A letter gap sent slightly short reads as a gap inside a character, and two letters merge into one that was never sent. Sending by hand, the discipline is to count evenly rather than to send fast.

The clearest example is SOS

The distress signal is three dits, three dahs and three dits. Sent with letter gaps, those are the three letters S, O and S. Sent with only one-unit gaps throughout, they are a single run of nine marks, and that run is the signal itself.

The International Telecommunication Union’s record of the 1906 Berlin conference that adopted it writes the signal as one group, which is why the drawing on our SOS page keeps the same short space between all nine marks.

Writing the gaps down

Morse written as text has to show the gaps somehow, and the usual convention is a single space between characters and a slash between words. That is what the morse code translator produces when you copy its output, and what it expects when you paste morse in to be decoded. If a string arrives with no spaces at all, the gaps are gone and nothing can reliably put them back.

Questions people ask next

How long is the space between letters in morse code?

Three units, the same length as a dah. At 20 words per minute that is 180 milliseconds.

How long is the space between words in morse code?

Seven units, which is 420 milliseconds at 20 words per minute and 1.68 seconds at 5 WPM.

How do you write spaces in morse code?

A single space between characters and a slash between words is the usual convention in text. The copyable morse on this site is written that way.

What happens if you leave the spaces out?

The marks regroup. Three dits, three dahs and three dits sent with letter gaps read as S, O and S; sent without them they are the SOS distress signal.

Is the gap inside a letter the same as a dit?

The same length, yes: one unit. It is silence rather than sound, but the clock treats it identically.

Sources

Codes and timing follow Recommendation ITU-R M.1677-1 (10/2009), International Morse code (International Telecommunication Union, 2009).
International Radiotelegraph Conference (Berlin, 1906) (International Telecommunication Union).