How does the reverse A1Z26 work?

In reverse A1Z26, the mapping is inverted: Z=1, Y=2, X=3 ... A=26. This is sometimes called 'A26Z1' or 'reverse alphabetical.' It is a simple variant that requires the same brute-force resistance as A1Z26 — essentially none — but adds a small layer of obscurity.

What is an offset cipher?

An offset cipher shifts the starting value. Instead of A=1, you might use A=0 (zero-indexed) or A=65 (ASCII values). A custom offset lets you set any starting number. This is used in some programming puzzles and custom code systems.

Where is the A1Z26 cipher used?

A1Z26 appears in the animated series Gravity Falls as a cipher used in episode end credits. It is also common in escape rooms, puzzle books, and online ARGs (alternate reality games). Because it is so simple, it is never used for real security — only for entertainment and learning purposes.

Letters to Numbers — A1Z26 Cipher

A=1, B=2 ... Z=26. Encode, decode, reverse, offset, and sum letter values.

Starting offset (A=?): Default: 1 (standard A1Z26)

Separator: Word separator:

Plain Text

Number Codes

Type a message above to convert letters to numbers.

How to Use the A1Z26 Cipher Tool

Encode — type plain text. Each letter becomes its position number (A=1 … Z=26, or use a custom offset).
Decode — enter numbers separated by spaces. Each number is mapped back to its letter.
Sum mode — see the total numerical value for each word and the full letter-by-letter breakdown.
Reverse (Z=1) — invert the mapping so Z=1, Y=2 … A=26.
Adjust offset — change the starting value (e.g. A=0 for zero-indexed, A=65 for ASCII).
Adjust separators — choose how numbers within a word and between words are separated.

What is the A1Z26 Cipher?

The A1Z26 cipher is the simplest of all substitution ciphers. Rather than replacing one letter with another letter (as Caesar cipher does), it replaces each letter with its numerical position in the alphabet: A becomes 1, B becomes 2, C becomes 3, and so on up to Z which becomes 26. The cipher is fully symmetric — encoding and decoding use the same table. To decode, simply look up each number in the table and write down the corresponding letter.

The cipher is named A1Z26 because A maps to 1 and Z maps to 26, which succinctly describes the entire encoding scheme. It appears under many names: the Letter-Number cipher, Numbered Alphabet, Letter Code, or simply "A=1 B=2."

Offset Variants

The standard A1Z26 uses offset 1, but several variants shift this baseline. The zero-indexed version (A=0, B=1 … Z=25) is common in computer science contexts where arrays are zero-based. ASCII values (A=65, B=66 … Z=90) are used in programming and represent the Unicode code points for uppercase letters. Some puzzle designers use arbitrary offsets — for example A=10 — to produce larger numbers that are harder to guess.

Sum / Numerology Mode

Sum mode adds up the A1Z26 values for every letter in a word. For example, HELLO = 8+5+12+12+15 = 52. This calculation is sometimes called "word numerology" or a "letter sum." It appears in puzzles, crossword clues ("This word has a letter sum of 52"), and in some numerological traditions that assign meaning to the numerical value of names. Note that many different words share the same sum — EHLLO, HMILO, and dozens of others also sum to 52 — so the sum alone cannot uniquely identify a word.

Gravity Falls and Pop Culture

The A1Z26 cipher gained wide recognition through the animated TV series Gravity Falls (2012–2016), created by Alex Hirsch. The show used A1Z26 as one of its end-credits ciphers, hidden in messages for viewers to decode. Along with Caesar cipher and Atbash, A1Z26 formed part of the show's evolving code system that viewers enthusiastically decoded, contributing to one of television's most engaged fandoms. As a result, A1Z26 is now one of the first ciphers many young people encounter.

Security

A1Z26 provides no meaningful security. An attacker who sees a sequence of numbers can immediately guess the encoding scheme and decode the message in seconds without any key. For actual secure communication, use modern encryption like AES-256, which this tool does not implement. A1Z26 is exclusively for puzzles, games, and educational purposes. For related historical ciphers, see Dancing Men, Scytale, and Baudot Code.

Frequently Asked Questions

The A1Z26 cipher replaces each letter with its position number: A=1, B=2, C=3 … Z=26. It is one of the simplest ciphers and appears widely in puzzles, escape rooms, and games like Gravity Falls.

In reverse A1Z26, the mapping is inverted: Z=1, Y=2, X=3 … A=26. Sometimes called "A26Z1." It is a simple variant that adds a small layer of obscurity but no real security.

Sum mode adds up all A1Z26 values in a word to produce a single number. For example HELLO = 8+5+12+12+15 = 52. This is sometimes called "word numerology" and appears in puzzles and number games.

An offset cipher shifts the starting value. Instead of A=1 you might use A=0 (zero-indexed) or A=65 (ASCII). The offset control lets you set any starting number for use in custom code systems.

A1Z26 appears in Gravity Falls end-credits ciphers, escape rooms, puzzle books, and online ARGs. It is never used for real security — only for entertainment and learning purposes.