Letters to Numbers Converter (A=1, B=2 … Z=26 cipher)

Understanding the letters to numbers converter — concept and principle

This converter replaces each letter with its position in the alphabet: A = 1, B = 2 … Z = 26, the simple cipher often called A1Z26. It can also use A = 0 … Z = 25, as in programming and the Caesar cipher, separates numbers within a word by hyphens, spaces or commas, and adds up the letter values for word puzzles.

How it is calculated

Value = position in the 26-letter basic Latin alphabet (A = 1 … Z = 26)

With A = 0 numbering: value − 1

Upper and lower case give the same value

Words are separated by " / "; digits, punctuation, accented letters and other scripts are skipped and counted

Sum = total of all letter values

The principle

The basic Latin alphabet has a fixed order shared by ASCII and Unicode, where A is code 65 and a is code 97. Subtracting 64 from a capital letter's code, or 96 from a small letter's, gives its position. That makes A1Z26 the simplest substitution cipher: easy to encode and decode, but offering no real secrecy. The A = 0 version matches how modular arithmetic numbers letters, which is used in shift ciphers such as Caesar's.

Worked example

Default inputs: "Hello World", A = 1 … Z = 26, hyphens.

1. H = 8, E = 5, L = 12, L = 12, O = 15 → 8-5-12-12-15.
2. W = 23, O = 15, R = 18, L = 12, D = 4 → 23-15-18-12-4.
3. Result: 8-5-12-12-15 / 23-15-18-12-4.
4. Sum = 52 + 72 = 124.
5. Letters converted = 10; other characters skipped = 0.

How to read the result

Use the numbers for puzzles, escape rooms, classroom activities or simple coded notes. The sum is used in word games that assign a "value" to a word. To decode, use the numbers to letters converter with the same numbering and separators.

Common mistakes

• Mixing A = 1 and A = 0 numbering between encoder and decoder.
• Forgetting separators, which makes 1-2 (AB) and 12 (L) ambiguous.
• Expecting accented letters or Hangul to convert; they are skipped.

Frequently asked questions

What is the A1Z26 cipher?

A cipher that replaces each letter with its alphabet position, A = 1 to Z = 26.

Why use A = 0?

Ciphers based on modular arithmetic, such as the Caesar shift, number letters from 0.

Are capitals different from small letters?

No, both give the same value.

What is the value of "abc"?

1 + 2 + 3 = 6 with A = 1.

Sources: ISO basic Latin alphabet letter order (ISO/IEC 646; Unicode Basic Latin block, U+0041–U+005A and U+0061–U+007A)