Does A1Z26 need a key?

Standard A1Z26 uses the fixed mapping A=1 to Z=26, with no keyword. Shifted, reversed or combined cipher variants need a separate convention and are not supported here.

Can I decode joined digits without separators?

Use explicit spaces or dashes between numbers. Joined digits can have multiple interpretations, so the tool does not guess where each number ends.

Are spaces, case and punctuation preserved?

Word breaks follow the selected separator convention. Letters decode uppercase; punctuation and other unsupported source characters are dropped and counted.

A1Z26 Cipher Translator: Letters and Numbers

A1Z26 substitutes alphabet positions for letters: A is 1 and Z is 26. This example decodes 8 5 12 12 15 / 23 15 18 12 4 to HELLO WORLD. Space mode uses / between words; dash mode uses a space between words, as in 8-5-12-12-15 23-15-18-12-4. The complete alphabet-number mapping and first calculations are visible. Numbers outside 1 to 26 are errors.

Cipher text28 characters

Plain textA1Z26, numbers separated by spaces

HELLO WORLD

decode A = 1 to Z = 26; numbers separated by spaces and / between words; case is not kept; digits, punctuation and letters outside A to Z are dropped

letter	A	B	C	D	E	F	G	H	I
number	1	2	3	4	5	6	7	8	9
letter	J	K	L	M	N	O	P	Q	R
number	10	11	12	13	14	15	16	17	18
letter	S	T	U	V	W	X	Y	Z
number	19	20	21	22	23	24	25	26

8the 8th letter, H
5the 5th letter, E
12the 12th letter, L
12the 12th letter, L
15the 15th letter, O
23the 23rd letter, W
15the 15th letter, O
18the 18th letter, R
12the 12th letter, L
4the 4th letter, D

encode encode each letter as its place in A to Z

Separator

Method: A1Z26, numbers separated by spaces

Numbers read: 10

Encode: encode each letter as its place in A to Z

Each letter becomes its place in the alphabet, A = 1 to Z = 26.

Textbook checks, one per method

Each row is worked by the same code as the stage above. Load puts it in the workbench with its keys.

Caesar, shift 3ABCXYZ
DEFABC
Keyword KRYPTOSKNOWLEDGE IS POWER
DGHVETPST BM IHVTL
Polybius 5 x 5, I and J share cell 24JAM
24 11 32, which decodes as IAM
A1Z26, numbers separated by spaces1 26
AZ
Nihilist, square ZEBRAS, key RUSSIANDYNAMITE WINTER PALACE
37 106 62 36 67 47 86 26 / 104 53 62 77 27 55 / 57 66 55 36 54 27
Book cipher, a 40-word reference text3 17 52
error: word 52 is outside the 40-word reference, and nothing is guessed
One-time pad, key XMCKLHELLO
EQNVZ

Puzzles and teaching, not secrets. These are historical and puzzle ciphers. Caesar has only 25 shifts on A to Z, so the ranked list that Decode shows reads most messages without the key, and keyword, Polybius and A1Z26 text gives way to letter counting. The one-time pad mode shows the arithmetic of a key you type and nothing more: this tool does not make keys and makes no claim that a message stays secret.

Accuracy. Each method follows the convention shown beside it: Caesar shifts count from 0 at the first letter of the alphabet and wrap after the last, the 5 x 5 Polybius and Nihilist squares give I and J one cell, A1Z26 reads 1 26 as AZ, and a book number outside your reference is an error, never a guess. The ranked list of Caesar shifts is an estimate from English letter frequency. These are historical and puzzle ciphers, not modern secure encryption, and the one-time pad mode only shows the arithmetic of the key you type, with no claim that it keeps a message secret.

Common questions

Does A1Z26 need a key?: Standard A1Z26 uses the fixed mapping A=1 to Z=26, with no keyword. Shifted, reversed or combined cipher variants need a separate convention and are not supported here.
Can I decode joined digits without separators?: Use explicit spaces or dashes between numbers. Joined digits can have multiple interpretations, so the tool does not guess where each number ends.
Are spaces, case and punctuation preserved?: Word breaks follow the selected separator convention. Letters decode uppercase; punctuation and other unsupported source characters are dropped and counted.

Each method follows the convention shown beside it: Caesar shifts count from 0 at the first letter of the alphabet and wrap after the last, the 5 x 5 Polybius and Nihilist squares give I and J one cell, A1Z26 reads 1 26 as AZ, and a book number outside your reference is an error, never a guess. The ranked list of Caesar shifts is an estimate from English letter frequency. These are historical and puzzle ciphers, not modern secure encryption, and the one-time pad mode only shows the arithmetic of the key you type, with no claim that it keeps a message secret.