Number Base Converter

Convert numbers between binary, octal, decimal and hexadecimal.

About this number base converter

Type a number into any field and the other three update instantly. Binary (base 2) uses 0 and 1, octal (base 8) uses 0-7, decimal (base 10) is everyday counting, and hexadecimal (base 16) adds the letters A-F. Conversion runs in your browser using BigInt, so very large values stay exact and nothing is sent to a server.

  • Only non-negative whole numbers are supported.
  • Hex input is case-insensitive; output is shown in uppercase.
  • Don't add prefixes like 0x or 0b.

Frequently asked questions

How do I convert binary to decimal?

Paste the binary number into the Binary field. The decimal value appears in the Decimal field immediately.

Is there a size limit?

No fixed limit. BigInt handles numbers far beyond the normal 64-bit range without rounding.

Why does it say my number is invalid?

Each field accepts only its own digits, for example just 0 and 1 in Binary. Spaces, decimal points and minus signs aren't supported.