Why 0 is interesting
Zero in morse is five straight dashes — the single longest numeric code. In ham radio contest exchanges, operators substitute a single T (one dash) as a cut-number to save time, turning “599” into “5NN” at 40 WPM.
Cultural and numerical context
Zero is all dashes — the most emphatic, longest-duration morse digit to send.
How to remember 0 in morse
All dashes, all the same — like a fence with five identical posts. Of all ten digits, zero is the only one that’s a single repeated symbol, which makes it instantly recognizable by ear even at high speed. Hear five dashes in a row and there’s nothing else it can be.
Where you’ll hear 0 in real morse traffic
You’ll hear zero on every signal-report exchange in contest CW (599 is “five-nine-nine” meaning perfect copy plus arbitrary 9 = signal strength), in date-of-month ticker updates on maritime weather broadcasts, and in airfield runway numbers (e.g., runway 27 cut for brevity to “two seven” — but 09 still gets read as “zero nine”).
NATO & aviation phonetic for 0
“Zero” in NATO phonetic. Aviation prefers the same word — strict no-substitution rule, since the older “oh” can be confused with the letter O on a noisy frequency.
Practice tip for drilling 0
Train yourself to hear zero as a single rhythmic block, not as five separate dashes. The ear should register a long sustained “daaaaah” with even spacing, distinct from the broken rhythm of any other digit. Once that gestalt clicks, zero becomes one of the easiest digits to copy by ear.
How long 0 takes to send
Zero is the longest digit in morse, full stop. Five dahs at three units each, plus the four one-unit gaps between them, comes to 19 units — no other digit reaches that. At 20 WPM, where a unit lasts 60 ms, a single zero occupies 1,140 ms of airtime: more than a full second for one character. That weight is exactly why serious contest operators almost never send zero in full.
A palindrome of pure dashes
Reverse ----- and you get ----- again: zero is one of only two palindromic digits (5, its all-dit opposite, is the other). It’s also the only digit containing no dits at all — and the only one with no duration twin. Every other digit shares its total length with exactly one partner; 19-unit zero stands alone at the top of the scale.
Cut-number shorthand: T for 0
The cut for zero is T (-): one dah standing in for five. That trims 19 units to 3 — an 84% saving, the deepest absolute cut in the whole cut-number system. It’s why a contest serial like 100 can go out as A-T-T: three characters, none of them at full digit weight.
All ten digits at a glance
See the full numbers explainer for why every digit is five elements, or the alphabet for letter codes.
Frequently asked questions
What is the number 0 in morse code?
The digit 0 in international morse code is "-----" — a five-element pattern like every other digit.
How long does 0 take to send in morse?
0 (-----) is 0 dits and 5 dahs, which with inter-element gaps totals 19 timing units — 1140 ms at 20 WPM. Digits range from 9 units (5) to 19 units (0).
What's the cut-number alias for 0?
At high contest speeds, operators abbreviate 0 with the letter T, which is shorter in morse. This is called cut-number shorthand and is context-specific to fast CW operation.