8 Ways to Convert Letters to Numbers — Which Method to Use?

There is not just one way to convert letters to numbers. There are at least eight widely used methods, each with different origins, different output formats, and different ideal use cases. Whether you are a student, a programmer, a puzzle designer, or someone creating a personal code, the method you choose changes the result dramatically. This guide is the definitive letters to numbers converterreference: we compare all eight methods side by side, show how "HELLO" looks in each, and provide a decision matrix to help you choose the right one.

The Master Comparison: "HELLO" in All 8 Methods

The same five letters produce eight completely different numeric representations. Let us explore each method in detail.

Method 1: A1Z26 (Alphabet Position)

Rule: A=1, B=2, C=3, ... Z=26

The A1Z26 system is the most intuitive and widely used letters to numbers method. Each letter simply equals its position in the alphabet. It has been used for centuries in puzzles, ciphers, numerology, and education.

Example: HELLO = 8, 5, 12, 12, 15

Pros

• Intuitive and easy to learn (no math beyond counting)
• Compact output (1-2 digits per letter)
• Universally understood in puzzle and cipher communities
• Foundation for numerology calculations

Cons

• No case distinction (A and a both equal 1)
• No support for digits, spaces, or punctuation
• Can be ambiguous without separators ("112" could be 1-1-2 or 11-2)

Best for: Education, puzzles, coded messages, numerology, tattoos, and any task where you only need letters.

Method 2: A0Z25 (Zero-Indexed Position)

Rule: A=0, B=1, C=2, ... Z=25

The zero-indexed version of A1Z26, where A starts at 0 instead of 1. This matches how most programming languages index arrays and strings.

Example: HELLO = 7, 4, 11, 11, 14

Pros

• Aligns with programming conventions (zero-based indexing)
• Useful for modular arithmetic (mod 26 operations work cleanly)
• Used in cryptographic formulas (Caesar cipher math uses 0-25)

Cons

• Less intuitive for non-programmers (A=0 feels unnatural)
• Same character limitations as A1Z26
• Easy to confuse with A1Z26 (off-by-one errors)

Best for: Programming, mathematical cryptography, and any context where zero-based indexing is the standard.

Method 3: Reversed Alphabet (Z1A26)

Rule: A=26, B=25, C=24, ... Z=1

The reverse of A1Z26. The last letter of the alphabet gets 1, and the first letter gets 26. This is closely related to the Atbash cipher concept.

Example: HELLO = 19, 22, 15, 15, 12

Pros

• Adds an extra layer of obscurity to coded messages
• Interesting mathematical property: A1Z26 value + Reversed value always equals 27
• Good for teaching inverse operations and subtraction

Cons

• Less intuitive than A1Z26
• Not a widely recognized standard
• Same character limitations as A1Z26

Best for: Puzzles requiring an extra step, teaching inverse operations, and combining with A1Z26 for dual-layer coding.

Method 4: ASCII (Decimal)

Rule: A=65, B=66, ... Z=90 (uppercase) | a=97, b=98, ... z=122 (lowercase)

The ASCII system is the foundation of how computers represent text. Published in 1963, it assigns numbers 0-127 to 128 characters including letters, digits, punctuation, and control codes.

Example: HELLO = 72, 69, 76, 76, 79

Pros

• Industry standard used by every modern computer
• Case-sensitive (distinguishes A from a)
• Handles digits, spaces, punctuation, and control characters
• Mathematical relationship to A1Z26: uppercase ASCII = A1Z26 + 64

Cons

• Values are not intuitive (why does A start at 65?)
• Requires a reference table for most people
• Limited to 128 characters (no accented letters, no non-Latin scripts)

Best for: Programming, data processing, system administration, and any task where full character set support and case sensitivity are needed.

Method 5: Hexadecimal (Base-16 ASCII)

Rule: Each ASCII value expressed in hexadecimal (base-16, digits 0-9 and A-F)

Hexadecimal is a compact way to represent ASCII values. Each hex digit represents 4 binary bits, so two hex digits represent one byte (8 bits), which is one character. Use the hex converter to try it.

Example: HELLO = 48, 45, 4C, 4C, 4F

Pros

• More compact than binary (2 digits per character vs. 8)
• Standard representation in programming (memory addresses, color codes, byte values)
• Clean mapping: each hex digit = exactly 4 binary bits

Cons

• Requires understanding base-16 numbering
• Can be confused with regular numbers (is "45" decimal or hex?)
• Not intuitive for non-technical audiences

Best for: Programming, web development (CSS colors like #4C4F56), debugging, and representing binary data compactly.

Method 6: Binary (Base-2 ASCII)

Rule: Each ASCII value expressed in binary (base-2, 8 bits per character)

Binary encoding represents each character as a sequence of 0s and 1s. This is the most fundamental representation, as it directly corresponds to how data is stored in computer hardware.

Example: HELLO = 01001000, 01000101, 01001100, 01001100, 01001111

Pros

• Directly represents how computers store data
• Essential for understanding computer science fundamentals
• Visually striking (popular for art and tattoo designs)
• No ambiguity with fixed 8-bit chunks

Cons

• Very long output (8 digits per character)
• Difficult to read and write manually
• Impractical for hand-encoded messages

Best for: Computer science education, visual art, tattoo designs, and understanding digital data storage.

Method 7: T9 (Phone Keypad)

Rule: Letters mapped to phone keypad numbers with repetition (A=2, B=22, C=222, D=3, E=33, etc.)

The T9 system maps letters to number keys based on the standard phone keypad layout that became universal with mobile phones in the 1990s. Each key (2-9) covers 3-4 letters, and repetition of the key number indicates which letter on that key is intended.

Example: HELLO = 44, 33, 555, 555, 666

Pros

• Nostalgic and recognizable (anyone who used pre-smartphone phones knows it)
• Fun for retro-themed puzzles and messages
• Different visual aesthetic from other encoding methods

Cons

• Variable-length output (1-4 digits per letter)
• Ambiguous without separators (is "2222" one letter D or two letters AA?)
• Not a formal encoding standard
• Increasingly unfamiliar to younger generations

Best for: Retro puzzles, nostalgic messaging, escape room challenges, and creative encoding projects.

Method 8: Excel Column Notation

Rule: Letters represent spreadsheet column headers: A=1, B=2, ... Z=26, AA=27, AB=28, etc.

Excel column notation is a base-26 system where letters represent column positions in spreadsheets. For single letters A-Z, it is identical to A1Z26. But it extends beyond Z: column 27 is AA, column 28 is AB, column 702 is ZZ, and column 703 is AAA.

Example: HELLO = H(8), E(5), L(12), L(12), O(15) — same as A1Z26 for single letters. But "AZ" = 52, "BA" = 53.

Pros

• Extends naturally beyond 26 (supports multi-letter column references)
• Familiar to anyone who uses Excel, Google Sheets, or LibreOffice Calc
• Useful for spreadsheet automation and data processing

Cons

• Identical to A1Z26 for single letters (only differs for multi-letter sequences)
• The base-26 math is non-trivial for column numbers above 26
• Narrow use case (primarily spreadsheet contexts)

Best for: Spreadsheet development, data analysis, and converting between column letters and numbers in Excel formulas.

Decision Matrix: Which Method Should You Use?

Decision Flowchart: "Which Method Should I Use?"

1. Is this for a computer or for humans?
   • Computer → Go to step 2
   • Humans → Go to step 4
2. Do you need case sensitivity and special characters?
   • Yes → ASCII (decimal for readability, hex for programming)
   • No → Go to step 3
3. Do you need zero-based indexing?
   • Yes → A0Z25
   • No → A1Z26 (simplest for letter-only tasks)
4. Is this for education, puzzles, or personal coding?
   • Yes → A1Z26 (easiest to learn and teach)
   • No → Go to step 5
5. Is visual impact important (tattoo, art, design)?
   • Want compact numbers → A1Z26
   • Want dramatic 0/1 patterns → Binary
   • Want retro aesthetic → T9

Mathematical Relationships Between Methods

The eight methods are not independent systems. Many are mathematically related.

• A0Z25 = A1Z26 - 1: Every A0Z25 value is exactly one less than the corresponding A1Z26 value.
• Reversed = 27 - A1Z26: The reversed-alphabet value is always 27 minus the A1Z26 value.
• ASCII (uppercase) = A1Z26 + 64: Add 64 to any A1Z26 value to get the ASCII code.
• ASCII (lowercase) = A1Z26 + 96: Add 96 for lowercase ASCII values.
• Hex = ASCII in base-16: The hex value is just the ASCII decimal value written in hexadecimal.
• Binary = ASCII in base-2: The binary value is the ASCII decimal value written in binary.
• Excel (single letter) = A1Z26: For single letters, Excel column numbers are identical to A1Z26.

This means if you know the A1Z26 value, you can derive five of the other seven methods through simple arithmetic. A1Z26 is truly the foundation.

Full Reference: "HELLO" with All Details

A1Z26 and Excel produce the shortest output for single letters (7 digits total for "HELLO"). Binary produces the longest (40 digits). This output length difference is a major practical consideration for space-constrained applications.

Try Every Method Yourself

The best way to understand these eight methods is to try them. Use any of the converters below to encode your own text and see the results side by side.

• A1Z26 Converter — Alphabet position (A=1, Z=26)
• ASCII Converter — Standard computing encoding
• Binary Converter — Base-2 representation
• Hex Converter — Base-16 representation
• T9 Converter — Phone keypad encoding
• Excel Column Converter — Spreadsheet column notation
• Cipher Comparison Chart — All methods side by side