ASCII to Binary Converter

ASCII codes and binary

ASCII gives each of 128 characters a number from 0 to 127. Converting a character to binary means writing its code in base 2:

The layout is deliberate: digits 0–9 are 48–57, so subtracting 48 gives the digit's value, and lower-case letters are exactly 32 above their capitals.

7-bit vs 8-bit output

ASCII was designed as a 7-bit code, so every value fits in seven bits and the highest code, 127, is 1111111. Computers store characters in 8-bit bytes, so most tools, including this one by default, add a leading 0: 01000001 rather than 1000001.

Use 7 bits when a textbook or exercise asks for “7-bit ASCII”, or when you are working with serial protocols and old systems that transmit seven data bits. The values are the same; only the leading zero changes.

ASCII table (0-127)

The searchable table under the converter lists all 128 codes with decimal, hex and 8-bit binary values. Type a single character to find its code, a number (decimal or hex such as 0x41) to find its character, a full byte such as 01000001, or part of a control character's name (“escape”, “line feed”).

Printable characters run from 32 (space) to 126 (~). The rest are control characters.

Control characters

Codes 0–31 and 127 are not printable; they were instructions for teleprinters and terminals. A few are still used every day:

Typing a tab or new line in the input converts it like any other character, and the breakdown names it.

ASCII vs Unicode

Unicode includes ASCII as its first 128 code points, so A is 65 in both. Beyond 127 they diverge: “extended ASCII” is not one standard but many code pages (Windows-1252, ISO 8859-1 and others) that assign 128–255 differently. Modern text uses Unicode, stored as UTF-8. This converter rejects characters above 127 and tells you which ones; convert those with text to binary (UTF-8) or look up their code points in the Unicode converter.