What is ASCII?
ASCII (American Standard Code for Information Interchange) is a character encoding that maps 128 characters — English letters, digits, punctuation, and control codes — to the numbers 0–127. For example, "A" is 65 and "a" is 97.
ASCII is the foundation that modern encodings build on: the first 128 code points of UTF-8 and Unicode are identical to ASCII.
Key points
- Maps 128 characters to the numbers 0–127 (7 bits).
- "A" = 65, "a" = 97, "0" = 48.
- Includes control codes like newline (10) and tab (9).
- The first 128 Unicode/UTF-8 code points match ASCII.
Example
A = 65 a = 97 0 = 48 space = 32
Common uses
- Representing plain English text
- Defining control characters (newline, tab)
- The basis of UTF-8 compatibility
- Low-level text and protocol work