International radiotelephony spelling alphabet
NATO phonetic alphabet
Spell letters and digits as standardized radio words, or decode a clearly separated sequence back to uppercase text.
01 / Converter
Choose a direction
ASCII letters and digits are supported. Spaces, tabs, and line breaks form word boundaries.
One space separates characters. A spaced slash, / , separates words.
Ready to spell text.
02 / Format
Exact spellings and separators
SPELL
Letters and figures
Letters are case-insensitive and become canonical code words. Digits become the written figure names shown in the NATO reference.
DECODE
Token boundaries
ASCII whitespace separates code words. A single slash separates original words. Capitalization does not affect decoding.
OFFICIAL
No silent substitutions
Use Alfa, Juliett, and X-ray. Aliases, punctuation, unknown words, and empty slash groups produce an error.
SOS
Sierra Oscar Sierra
03 / A-Z reference
Official code words
The internationally adopted spellings include Alfa with an F and Juliett with two final Ts. These forms help speakers of different languages pronounce the words consistently.
| Letter | Code word | Letter | Code word |
|---|---|---|---|
| A | Alfa | N | November |
| B | Bravo | O | Oscar |
| C | Charlie | P | Papa |
| D | Delta | Q | Quebec |
| E | Echo | R | Romeo |
| F | Foxtrot | S | Sierra |
| G | Golf | T | Tango |
| H | Hotel | U | Uniform |
| I | India | V | Victor |
| J | Juliett | W | Whiskey |
| K | Kilo | X | X-ray |
| L | Lima | Y | Yankee |
| M | Mike | Z | Zulu |
04 / Figures
Digit names and reading cues
The converter writes the figure names below. The reading cues show the approximate English radio pronunciations in NATO's public reference poster.
| Digit | Written | Reading cue | Digit | Written | Reading cue |
|---|---|---|---|---|---|
| 0 | Zero | zee-ro | 5 | Five | fife |
| 1 | One | wun | 6 | Six | six |
| 2 | Two | too | 7 | Seven | sev-en |
| 3 | Three | tree | 8 | Eight | ait |
| 4 | Four | fow-er | 9 | Nine | nin-er |
05 / Limits
Behavior and scope
- Source input is limited to 1,500 Unicode code points and 3,000 UTF-16 code units. Generated output is limited to 20,000 code units.
- Only ASCII letters, digits, and ASCII whitespace are accepted in spelling mode. Unsupported punctuation and non-ASCII characters are identified rather than skipped.
- Input remains in place after an error. Editing the source or changing mode clears the earlier result so stale text cannot be copied or swapped.
- This is a spelling alphabet, not phonetic transcription such as IPA. It is also not encryption, because anyone familiar with the word list can read it.
- The reference follows the NATO public alphabet and the ICAO history of Annex 10. This tool does not play or recognize speech.