ASCII / Unicode Value Calculator
Look up ASCII and Unicode values for any character, or convert character codes to text.
Character → Code
Code → Character
What Is the ASCII / Unicode Value Calculator?
The ASCII Value Calculator converts between characters and their ASCII (American Standard Code for Information Interchange) decimal, hexadecimal, octal, and binary values. It supports the full ASCII table (0-127) and extended ASCII (128-255), and shows UTF-8 encoding for Unicode characters.
Formula
How to Use
Enter a character, string, or decimal/hex ASCII code. The calculator displays the decimal, hexadecimal, octal, and binary values for each character. For a full string, it shows all values in a table. Enter a number (0-127) to find the corresponding ASCII character.
Example Calculation
Character 'A': decimal=65, hex=0x41, octal=101, binary=01000001. 'Hello': H=72, e=101, l=108, l=108, o=111. Space=32=0x20. Tab=9=0x09. Null=0=0x00.
Understanding ASCII / Unicode Value
ASCII is the foundational character encoding that made digital text communication possible. Standardized in 1963 by the American Standards Association, it assigns 7-bit codes (0-127) to the Latin alphabet, digits, punctuation, and control characters. Despite its age, ASCII remains relevant because it is a subset of every modern text encoding — every UTF-8 encoded text file that uses only ASCII characters is identical to a pure ASCII file.
The structure of ASCII was carefully designed for practical use: digits 0-9 are at codes 48-57 (sequential, easy to convert by adding/subtracting 48), uppercase letters are at 65-90, and lowercase at 97-122. The 32-unit difference between upper and lower case allows case conversion by flipping a single bit. Control characters (0-31) encode formatting commands that originate from teletype machine operations.
Understanding ASCII codes is fundamental for programming tasks: parsing text files, implementing string operations, writing lexers and parsers, processing network protocols (most use ASCII framing), manipulating character data in embedded systems, and debugging binary data that contains embedded text. The hex representation (0x41 = 'A') is particularly useful in debugging and hex editor work.
Frequently Asked Questions
What is ASCII?
ASCII (American Standard Code for Information Interchange) is a 7-bit character encoding standard that assigns integers 0-127 to characters including letters, digits, punctuation, and control codes. Developed in 1963, it remains the foundation of all modern text encoding.
What are ASCII control characters?
ASCII 0-31 and 127 are control characters: 0=null, 8=backspace, 9=tab, 10=line feed (newline), 13=carriage return, 27=escape, 32=space (first printable character). These are used for text formatting and terminal control.
What is the difference between ASCII and Unicode?
ASCII encodes only 128 characters (English letters, digits, basic symbols). Unicode encodes over 143,000 characters covering all world scripts. ASCII is a subset of Unicode — all ASCII values are identical in Unicode.
Why is uppercase 'A' = 65 and lowercase 'a' = 97?
The 32-value difference between uppercase (65-90) and lowercase (97-122) allows simple bit manipulation: toggling bit 5 (adding/subtracting 32) converts between cases. This is why case conversion is a fast operation.
Is this calculator free?
Yes, completely free with no account needed.