Number Base Converter

Convert numbers between decimal, hexadecimal, binary, and octal. Supports large numbers. Everything runs in your browser.

Decimal (base 10)
255
Hexadecimal (base 16)
0xFF
Binary (base 2)
0b1111 1111
Octal (base 8)
0o377

Bit Information

Bits needed: 8
Bytes needed: 1
Is power of 2: No

Quick Examples

About Number Base Converter

This free online number base converter lets you convert between decimal (base 10), hexadecimal (base 16), binary (base 2), and octal (base 8) number systems instantly. It supports arbitrarily large numbers using JavaScript BigInt.

Number Systems Explained

  • Decimal (base 10) — The standard number system using digits 0-9
  • Hexadecimal (base 16) — Uses digits 0-9 and letters A-F, commonly used for colors and memory addresses
  • Binary (base 2) — Uses only 0 and 1, the fundamental language of computers
  • Octal (base 8) — Uses digits 0-7, commonly used in Unix file permissions

Common Conversions

  • 255 decimal = FF hex = 11111111 binary = 377 octal
  • 256 decimal = 100 hex = 100000000 binary
  • DEADBEEF hex = 3,735,928,559 decimal