Each number is its place in the alphabet
A1Z26 replaces every letter with its number in the alphabet: A is 1, B is 2, and so on to Z at 26. To decode, read each number back to its letter; to encode, do the reverse. There is no key or shift — it is a straight one-to-one swap, which is why puzzle setters use it as a first, easy layer.
The full A=1 to Z=26 table
| Letter | No. | Letter | No. | Letter | No. |
|---|---|---|---|---|---|
| A | 1 | J | 10 | S | 19 |
| B | 2 | K | 11 | T | 20 |
| C | 3 | L | 12 | U | 21 |
| D | 4 | M | 13 | V | 22 |
| E | 5 | N | 14 | W | 23 |
| F | 6 | O | 15 | X | 24 |
| G | 7 | P | 16 | Y | 25 |
| H | 8 | Q | 17 | Z | 26 |
| I | 9 | R | 18 | — | — |
Case does not matter — a and A are both 1. Spaces and punctuation are usually left as-is between the coded letters.
Look-alike schemes people confuse with A1Z26
- Reverse A1Z26. The alphabet runs backwards: Z=1, Y=2, up to A=26. To convert, subtract from 27 (a plain A1Z26 value of 8 becomes 27 − 8 = 19).
- ASCII. Uppercase A starts at 65 and lowercase a at 97, so any code above 26 is almost certainly ASCII, not A1Z26.
- T9 phone keys. Only digits 2–9, often repeated (2=A, 22=B, 222=C). If you see short runs of the same digit, it is likely an old keypad code.
Common questions
How do I decode a sequence like 8 5 12 12 15?
Turn each number into its letter using A=1, B=2, up to Z=26. So 8 is H, 5 is E, 12 is L, 12 is L, 15 is O, which spells HELLO. Keep the numbers separated by spaces or commas so the reader knows where one letter ends.
What if a number is larger than 26?
A1Z26 only runs 1 to 26, so anything above 26 is not this cipher. Numbers like 65 or 72 are usually ASCII codes (A is 65), and pairs from 2 to 9 that repeat may be old phone T9 keys. Check the puzzle for a hint about which scheme it uses.
Why is spacing between the numbers so important?
Without a separator the digits are ambiguous. "123" could read as 1-2-3 (ABC), 12-3 (LC) or 1-23 (AW). Always write the numbers with spaces or commas between them so there is only one reading.
