Number Base Converter

Convert between binary, octal, decimal and hex.

Edit any field — the others update instantly. Values are exact integers (no rounding).

About the Number Base Converter

Convert numbers between binary, octal, decimal and hexadecimal with instant, two-way updates. A quick reference for developers working with bitmasks, colors, memory addresses and low-level data.

How to use it

  1. 1Type a number in any base — binary, octal, decimal or hex.
  2. 2All other bases update simultaneously.
  3. 3Copy the representation you need.

Binary, octal, decimal and hex, side by side

Numbers can be written in different bases, and low-level work moves between them constantly: binary shows the individual bits, hexadecimal packs those bits into a compact form used for colours and memory, and decimal is what humans read. Converting by hand is fiddly and error-prone. Enter a value in any base here and every other representation updates at once, so you can check a bitmask, decode a colour value, or read a hex address without reaching for a calculator or writing throwaway code.

Common uses

  • Inspecting the individual bits behind a bitmask or set of flags.
  • Converting a hex colour value to its decimal RGB components.
  • Translating a memory address or byte value between hex and decimal.

Frequently asked questions

Can I convert hex color values?
Yes — enter the hex digits to see their decimal and binary equivalents, handy for working with colors and flags.
Why do developers use hexadecimal so often?
Hex maps neatly onto binary — each hex digit is exactly four bits — so it's a compact, readable way to write byte values, colours and memory addresses without long strings of ones and zeros.