Convert between text characters and their ASCII numeric codes. Understand character representation in computing.
Last updated: 2026-03-28T00:00:00Z
Type any text to see its ASCII representation
ASCII (American Standard Code for Information Interchange) is a character encoding standard that represents text in computers and communication equipment. Developed in the 1960s, ASCII uses numeric codes from 0 to 127 to represent letters, numbers, punctuation marks, and control characters.
Each character you type on a keyboard has a corresponding ASCII value. For example, the letter 'A' is represented by the number 65, 'B' is 66, and so on. Lowercase letters start at 97 ('a'), and common punctuation marks have their own codes. This standardization allows different computer systems to exchange text data reliably.
ASCII is fundamental to computing and forms the foundation for more comprehensive encoding systems like UTF-8. Understanding ASCII is essential for programmers, especially when working with character manipulation, data transmission, or debugging text-related issues.
Let's convert "Hi!" to ASCII codes:
Uppercase letters (A-Z) have ASCII values 65-90, while lowercase letters (a-z) have values 97-122. There's exactly a difference of 32 between corresponding upper and lowercase letters (e.g., 'A' is 65, 'a' is 97).
No. ASCII only covers 128 characters (0-127) and is limited to English letters, numbers, and basic symbols. For international characters, emojis, or special symbols, use Unicode/UTF-8 encoding which extends ASCII.
Control characters (0-31) are non-printable characters that control text formatting or device behavior. Examples include newline (10), tab (9), carriage return (13), and escape (27). They're essential for text processing but don't display visually.
The space character (code 32) is a printable character that creates horizontal spacing. It's the boundary between control characters (0-31) and visible characters (33+). While it appears 'empty', it's a distinct character with its own ASCII value.
Add 32 to an uppercase letter's ASCII code to get its lowercase equivalent (A=65 → a=97). Subtract 32 from a lowercase letter to get uppercase (a=97 → A=65). This works for all letters A-Z and a-z.
The digit characters '0' through '9' have ASCII codes 48-57. This is different from their numeric values (0-9). To convert a digit character to its numeric value in programming, subtract 48 (e.g., '5' - '0' = 53 - 48 = 5).
Yes! ASCII remains fundamental to computing. UTF-8 (the modern standard) is backward-compatible with ASCII—the first 128 UTF-8 characters are identical to ASCII. Most programming languages, protocols, and file formats still rely on ASCII for basic text.
Standard ASCII only defines 0-127 (7 bits). Codes 128-255 are part of Extended ASCII, which varies by system. Modern systems use UTF-8 instead, where characters above 127 are represented using multiple bytes for international support.
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