ASCII Table — Complete Reference (0–127)

What is ASCII?

ASCII (American Standard Code for Information Interchange) is the 1960s character encoding that became the foundation of every modern text format. It defines 128 characters — codes 0 to 127 — covering English letters, digits, punctuation and a set of control characters. Every modern encoding (Latin-1, Windows-1252, UTF-8) is backwards-compatible with ASCII for the first 128 code points.

Reading the table

• Decimal — base-10, the way humans count.
• Hex — base-16, what you see in file dumps and code.
• Octal — base-8, used in some Unix contexts.
• Binary — base-2, the underlying bits.
• Char — the printable character (blank for non-printable controls).
• Name — the standard name (for control characters) or description.

Control characters (0–31, plus 127)

The first 32 characters and the last (127, DEL) are "control characters" — codes that originally controlled teletype machines and modems. Most are no longer used; a handful remain critical:

• 9 (TAB) — horizontal tab.
• 10 (LF) — line feed; the Unix newline.
• 13 (CR) — carriage return; combined with LF for Windows newlines (CRLF).
• 27 (ESC) — escape; the prefix for ANSI escape sequences (terminal colours).
• 32 (SPACE) — the space character, technically the first printable character.

Printable characters (33–126)

Codes 33 to 126 cover all visible characters: punctuation, digits (48–57), uppercase letters (65–90), lowercase letters (97–122), and additional symbols. Notable codes:

• 48 (0) through 57 (9) — digits.
• 65 (A) through 90 (Z) — uppercase letters.
• 97 (a) through 122 (z) — lowercase letters.
• 32 (SPACE), 33 (!), 34 ("), 35 (#) and so on.

Tips and conversions

• To convert uppercase to lowercase in ASCII, add 32 (or set the 6th bit).
• To check if a character is a digit: code is between 48 and 57.
• Letter codes are sequential — A=65, B=66, …, Z=90.
• The shift between digits and their numeric value is 48 — so digit char minus 48 = number.

FAQs

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