ASCII Encoding Guide
ASCII Character Encoding
The 128-character American Standard Code for Information Interchange and its role inside Unicode.
128 characters, one byte
ASCII defines 128 characters: 32 control codes, 95 printable characters, and the delete character. Values run from 0 to 127, which fit in a single byte.
Printable characters include letters, digits, punctuation, and a space. Control characters such as line feed and carriage return shape text and data streams.
65 = 41 = 10197 = 61 = 14110 = 0A = 012Decimal, hex, octal, binary
The same ASCII value can be written in decimal, hexadecimal, octal, or binary. The ASCII table on this site shows all four forms for every code.
A is decimal 65, hex 41, octal 101, and binary 01000001. These forms matter for protocols, low-level code, and character escapes.
ASCII inside Unicode
Unicode keeps every ASCII character at the same code point, so U+0041 is also ASCII 65. UTF-8 preserves ASCII bytes unchanged.
Extended ASCII is not one standard: different code pages map 128-255 differently. This hub keeps the original 0-127 table authoritative and explains extended forms in guides.