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Number/Base Converter

Convert between number bases

Convert numbers between binary, octal, decimal and hexadecimal - instantly as you type

Input (Decimal)
Binary11111111
Octal377
Decimal255
HexadecimalFF

About the number/base converter

The number base converter translates a value between the four bases used in computing and mathematics: binary (base 2), octal (base 8), decimal (base 10), and hexadecimal (base 16). Type any number, choose the base you are entering it in, and the equivalent value in every other base appears instantly below.

The converter supports arbitrarily large integers using BigInt, so it handles values well beyond the 32-bit and 64-bit limits common in programming. A leading 0b, 0o, or 0x prefix is optional and will be stripped automatically.

Supported bases

  • Binary — base 2 (digits 0–1)
  • Octal — base 8 (digits 0–7)
  • Decimal — base 10 (digits 0–9)
  • Hexadecimal — base 16 (digits 0–9, A–F)

How to use the number/base converter

  1. Enter a number

    Type the value you want to convert.

  2. Choose its base

    Select whether your input is binary, octal, decimal, or hexadecimal.

  3. Read every base at once

    The equivalent value in all four bases is shown below, ready to copy.

Frequently asked questions

How large a number can I convert?
The converter uses BigInt, so it handles arbitrarily large integers — far beyond the 64-bit limit of about 18 quintillion.
Do I need to add a 0x or 0b prefix?
No. Prefixes like 0b, 0o, and 0x are optional and stripped automatically. Just pick the base from the selector and type the digits.
Are hexadecimal letters case-sensitive?
No. Both uppercase and lowercase letters (A–F or a–f) are accepted, and the hexadecimal output is shown in uppercase.
Does it work offline?
The converter runs entirely in your browser, so once the page is loaded it works without an internet connection.
Is the number base converter free?
Yes, it is completely free and requires no account or sign-up.

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