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The ASCII table maps every character used in basic text encoding to a numeric code from 0 to 127 — a standard set as old as computing itself, defined back when 7 bits was all a character needed. Every programming language, terminal, and file format built since then still relies on this same underlying mapping for the basic Latin letters, digits, and punctuation, which is why knowing (or being able to quickly look up) a character's ASCII code remains genuinely useful for debugging. Whether you're decoding a raw byte dump, writing a parser that needs to check for a specific delimiter character, working with a legacy protocol, or just trying to remember which control code represents a tab versus a newline, having every code laid out in decimal, hex, octal, and binary side by side saves you from doing the base conversion by hand or hunting through documentation. This reference viewer lists each character alongside its code in all four common numeric bases, so you can look up a character's value or a value's character instantly.
How it works
Choose either the printable range (32-126, the characters you can actually type and see on screen) or the full range (0-127, which also includes non-printable control characters like newline, tab, and carriage return). The table then lists every character or control code in that range together with its numeric value expressed in decimal, hexadecimal, octal, and binary, so you can cross-reference between whichever base your current task is using.
- Enter range.
- Click Calculate to see your results.
Examples
Looking up a letter's code
Capital "A" is decimal 65, hex 0x41, octal 101, and binary 01000001 — exactly what this table displays for every character.
Looking up a control character
The newline character (often written \n in code) is decimal 10, hex 0x0A — a value that shows up constantly when debugging text files or network data that mixes line endings.
Converting a digit character to its code
The digit character "0" (as text, not the number zero) is decimal 48 — a common source of bugs when code mistakenly treats a character digit as its numeric value without subtracting this offset.
Who should use it
- Looking up a character's byte value while debugging a protocol or file format.
- Teaching reference for a programming or networking class.
- Identifying an unfamiliar control character found in a data dump.
Industry applications
- Software development
- Computer science education
- Network protocol debugging
Advantages
- Shows all four common numeric bases at once.
- Instant, no signup.
- Covers both printable characters and non-printable control codes.
Limitations
- Limited to the original 128-character ASCII set, not full Unicode.
Common mistakes to avoid
- Assuming ASCII covers accented letters or symbols beyond code 127 — those require Unicode/UTF-8 instead.
- Confusing the digit character "5" (code 53) with the actual number 5 — a frequent source of off-by-48 bugs when parsing character input.
- Mixing up carriage return and newline when debugging cross-platform line-ending issues.
Best practices
- Use the printable-only view when you just need visible characters; use the full view when debugging control characters in a data stream.
- When converting a digit character to its numeric value in code, remember to subtract 48 (or use your language's built-in conversion function instead of hardcoding the offset).
- Cross-check control character codes against this table before writing low-level file or protocol parsing logic.
Tips
- Pair with the Binary/Hex/Octal converters if you need to convert a specific value rather than browse the whole table.
- Bookmark the control-character range if you regularly debug file encoding or line-ending issues.