Free Online Number Base Converter
Type a number in any of the four fields — binary, octal, decimal, or hexadecimal — and the other three update instantly.
Binary (base 2)
Octal (base 8)
Decimal (base 10)
Hexadecimal (base 16)
Number Base Reference
Binary (base 2)
Uses only digits 0 and 1. The native language of digital hardware; every byte is 8 binary digits. Example: 202₁₀ = 11001010₂.
Octal (base 8)
Uses digits 0–7. Historically used in Unix file permissions (chmod 755) and as a compact alternative to binary — 3 binary digits map to one octal digit.
Decimal (base 10)
The everyday number system using digits 0–9. The default for humans and most high-level programming languages.
Hexadecimal (base 16)
Uses digits 0–9 and letters A–F. One hex digit represents exactly 4 binary bits, making it compact for memory addresses, colour codes (#FF6347), and byte values.