K in Morse Code (-.-): Symbol, Sound and Radio Meaning

What is K in Morse code?

The letter K is a three-signal character defined in International Morse Code (ITU-R M.1677-1), the standard used by amateur radio, aviation and maritime operators worldwide. K is one of the letters whose international code matches American Morse, so the -.- you learn today is a pattern telegraph operators sent in the 1800s.

How to send K in Morse code

To send K, give one long signal, one short signal and one long signal, keeping the dash three times as long as the dot. The method does not matter; the ratio does.

1. Sound (key, buzzer or voice): long tone, short tone, long tone. Say it aloud as "dah-dit-dah," never "dash dot dash," which breaks the rhythm.
2. Light (flashlight or phone torch): long flash, quick flash, long flash. Keep the lamp off for one unit between flashes.
3. Tap or knock: heavy tap, light tap, heavy tap. Taps carry no duration, so make the gap after each "dash" obviously longer.
4. On paper or in text: write −·− with no spaces inside the letter. Leave a three-unit gap before the next letter and a seven-unit gap (shown as a slash) before the next word.

If you ever need to signal "OK" with a flashlight, it is three long flashes, a pause, then this long-short-long K.

K in Morse code timing at different speeds

The sound of K changes with sending speed, but the proportions never do: the dot is one unit, each dash is three, and the two gaps inside the letter are one unit each. Morse speed is measured in words per minute using the 50-unit word PARIS, so one unit lasts 1200 ÷ WPM milliseconds.

At 5 WPM you can count the three signals; at 20 WPM K arrives in about half a second and the middle dit is a flick between two tones. Train your ear at or near the speed you plan to use, because a letter learned by counting at 5 WPM has to be relearned by sound later.

How to remember K (−·−)

The easiest way to remember K is its symmetry: the pattern reads the same forwards and backwards, long-short-long, with the dot sitting in the middle like filling in a sandwich. Its mirror image, R (·−·), is short-long-short, so learning the pair together fixes both.

Word mnemonics work if you match stress to length: KA-ra-TE and KAN-ga-ROO both land as dah-dit-dah. Mnemonics are a crutch for the first few days; drop them as soon as you can hear K as one sound rather than three parts, because counting signals is what caps most people at low speed.

Tap the rhythm on a desk while you say it, then listen to the audio at full speed. K is so distinct that at least one Koch-method trainer teaches it as the very first character of the alphabet.

Letters easily confused with K

K is most often mistaken for R, which has the same three-signal length with the lengths reversed, and for the longer letters C and Y, which start with K's pattern and then add one more signal.

When you hear a dah-dit-dah, the deciding moment is the silence after the second dash. If nothing follows within one unit, it was K; if a dit or dah arrives, you are hearing C or Y. Practice K next to C and Y so your ear learns to wait for that gap instead of guessing early.

What K means on the radio

Sent on its own at the end of a transmission, K is a prosign meaning "go ahead" or "over": a general invitation for any listening station to transmit. The same three signals that spell the letter carry this message, so there is nothing new to learn; context tells the receiver whether K is a letter in a word or the end of a turn.

Two related signals matter in a contact. KN (sent as one character, −·−−·) is the ITU-R M.1677-1 "invitation to a named station to transmit," used when the operator wants only the station they are already working to reply. SK marks the end of the contact altogether. On a busy band, ending with K invites anyone to call, while ending with KN politely closes the door.

This is also why a solo K is so recognizable to operators: they hear it at the end of almost every exchange, and many US call signs begin with the letter as well.

Words that use K

Practicing K inside real words trains the letter gap as well as the letter. Each word below separates letters with a space; between words you would leave a seven-unit gap.

OK is a useful first word because the three dashes of O make the shorter K that follows stand out, and KEY puts K and Y side by side, which is exactly the pair most people confuse.

Practice K on Morse Beacon

Use the player at the top of this page to hear the K Morse code sound and watch it flash, then switch to the Morse code translator to type words like OK and KEY and play them back at the speed you are training for. Listening to a letter 20 to 30 times in a short daily session does more than one long sitting.

Work the neighbors too: J (·−−−) and L (·−··) sit either side of K in the alphabet, and the full Morse code alphabet chart lets you drill K against R, C and Y. Sending K with your own key or light, then decoding it with the audio decoder, checks that your dash-to-dot ratio is right.