🔢 Binary Calculator

Convert between decimal, binary, hexadecimal, and octal instantly.

Decimal (Base 10)

Binary (Base 2)

Hexadecimal (Base 16)

Octal (Base 8)

Binary / Hex Converter — Number Base Conversion

Our binary calculator converts numbers between four numeral systems: Decimal (base 10, everyday numbers), Binary (base 2, used in computer systems and logic gates), Hexadecimal (base 16, used in programming, HTML colors, memory addresses), and Octal (base 8, used in Unix file permissions and older computing systems). Type in any field and all others update instantly.

Why Do Computers Use Binary?

Computers use binary because transistors have two states: on (1) and off (0). All data — numbers, text, images, and programs — is ultimately stored as binary. Hexadecimal is used as a shorthand for binary because each hex digit (0-F) represents exactly 4 binary digits, making long binary numbers much shorter to write. For example, the binary 11111111 = hex FF = decimal 255.