0 in Morse code

The number 0 is dash dash dash dash dash in International Morse code, said “dah-dah-dah-dah-dah”. Like every digit it has five elements: all five elements are dashes. It lasts 19 units, which is 1140 ms at 20 WPM.

Where 0 fits in the number pattern

All ten digits follow one rule, so learning the pattern teaches you every number. From 1 to 5 the dots grow from the left; from 6 to 0 the dashes do.

0 on a timing ruler

0 as a cut number

In contests and fast exchanges, operators often shorten digits to a letter, called a cut number. 0 is commonly cut to T (-), which saves 16 units every time. The listener knows a number is expected, so the letter cannot be misread.

Characters that sound like 0

These are the characters most often copied by mistake for 0, and why.

Can you hear the difference?

Listen, then pick the one you heard.

0 on the air

In contests 0 is often cut to a single dash, T, so a serial number like 100 goes out as 1TT.
Operators write zero with a slash (Ø) in logs so it cannot be read as the letter O. In Morse the two differ too: 0 is five dashes, O is three.

0 at a glance

Morse code: -----
Sounds like: dah-dah-dah-dah-dah
Length: 19 units
At 20 WPM: 1140 ms
Cut number: T
Koch order: 40 of 41, then X

Sources: codes from ITU-R M.1677-1, the International Morse code standard. Cut numbers and on-air usage follow common amateur radio practice.

Hear 0 at your speed