ASCII Table Complete Reference

Full 128-character ASCII table with decimal, hex, octal, and binary values plus control character meanings.

Control Characters (0-31)

The first 32 ASCII code points are non-printable control characters originally designed for teletype machines. Many are obsolete in modern usage, but several remain essential in terminals and protocols. For example, LF (line feed) and CR (carriage return) still delimit text lines, while ESC introduces escape sequences. NUL serves as a string terminator in C-style APIs. Transmitting most control characters over text protocols can cause unintended side effects.

NUL: Null character, value 0, string terminator in C
LF: Line feed, value 10, newline in Unix
CR: Carriage return, value 13, newline in classic Mac
ESC: Escape, value 27, introduces escape sequences
DEL: Delete, value 127, rubout in paper tape

Printable Characters (32-126)

Code points 32 through 126 are the printable ASCII characters, including the space at 32 and the tilde at 126. Digits 0-9 occupy the contiguous range 48-57, uppercase letters 65-90, and lowercase letters 97-122. Converting between cases is a single bit flip because the two ranges differ only by bit 5. This regularity enables fast, branchless case conversion in performance-critical code.

Extended ASCII

Code points 128-255 are not part of standard ASCII and are interpreted differently by each extended code page. Latin-1 (ISO-8859-1) fills them with Western European accented letters, while CP437 uses them for box-drawing glyphs. UTF-8 reuses the 128-255 range as continuation bytes, making raw high bytes ambiguous without an explicit encoding declaration. Always specify the encoding when handling bytes above 127.