Field reference
Morse code chart
Every letter and number in International Morse code, with how each one sounds, plus SOS and the timing that makes it readable. Print it, or keep it on your phone.
Letters A to Z
A dot is a short signal and a dash is a long one, three times as long. Say them aloud as "dit" and "dah" and they're easier to remember by sound than by sight.
- A
- dot dash
- B
- dash dot dot dot
- C
- dash dot dash dot
- D
- dash dot dot
- E
- dot
- F
- dot dot dash dot
- G
- dash dash dot
- H
- dot dot dot dot
- I
- dot dot
- J
- dot dash dash dash
- K
- dash dot dash
- L
- dot dash dot dot
- M
- dash dash
- N
- dash dot
- O
- dash dash dash
- P
- dot dash dash dot
- Q
- dash dash dot dash
- R
- dot dash dot
- S
- dot dot dot
- T
- dash
- U
- dot dot dash
- V
- dot dot dot dash
- W
- dot dash dash
- X
- dash dot dot dash
- Y
- dash dot dash dash
- Z
- dash dash dot dot
Numbers 0 to 9
Every number is five symbols long, and they follow a pattern: 1 to 5 add a dot at the front for each step, and 6 to 9 swap dots for dashes the same way. 0 is five dashes.
- 0
- dash dash dash dash dash
- 1
- dot dash dash dash dash
- 2
- dot dot dash dash dash
- 3
- dot dot dot dash dash
- 4
- dot dot dot dot dash
- 5
- dot dot dot dot dot
- 6
- dash dot dot dot dot
- 7
- dash dash dot dot dot
- 8
- dash dash dash dot dot
- 9
- dash dash dash dash dot
Shortest codes first
The most common letters in English got the shortest codes, so E and T are a single symbol. Learning the letters in this order means the ones you'll meet most are the first you know.
- 1 symbol
- E T
- 2 symbols
- A I M N
- 3 symbols
- D G K O R S U W
- 4 symbols
- B C F H J L P Q V X Y Z
SOS in Morse code
Three short, three long, three short
SOS is the international distress signal: three dots, three dashes, three dots, then a pause, repeated until someone answers. It was chosen because it's simple to send and hard to mistake. It doesn't stand for anything.
It works with anything that can be short or long: a flashlight, a car's headlights, a whistle or a horn, or knocking. With a light, make each flash a clear on and off, and point it toward whoever might see it.
Morse code timing
Morse is read by rhythm, so the gaps matter as much as the signals. Every length is a multiple of one dot:
| Element | Length |
|---|---|
| Dot | 1 unit |
| Dash | 3 units |
| Gap between dots and dashes in a letter | 1 unit |
| Gap between letters | 3 units |
| Gap between words | 7 units |
Keep the ratios and the speed can be anything. Slow and even beats fast and ragged, especially by light.
Offline in ColdBoot
Morse Code, with no signal.
ColdBoot's Morse Code tool keeps all of this on your phone and works without a connection:
- Alpha to Morse flashes a message you type with your phone's light, with an optional tone.
- Morse to Alpha decodes a reply as you tap in the dots and dashes.
- The trainer plays Morse for you to name, from single letters up to words and full sentences.
- The cheat sheet is this chart, sorted alphabetically or shortest pattern first.
- The Flashlight's SOS mode flashes SOS on repeat, with or without a tone.