A base is how many digits a number system uses. Binary uses 0–1, octal 0–7, decimal 0–9, and hexadecimal 0–9 plus A–F. The same quantity can be written in any base.

Binary, Hex & Octal Converter

Convert numbers between binary, octal, decimal, and hexadecimal instantly.

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Binary, Hex & Octal Converter — Programmers juggle number bases every day: IP addresses in decimal, memory addresses in hex, masks and flags in binary. Converting between them by hand is tedious and error-prone.

Conversions run locally in your browser — nothing is sent to a server.

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Qu’est-ce que Binary, Hex & Octal Converter ?

Programmers juggle number bases every day: IP addresses in decimal, memory addresses in hex, masks and flags in binary. Converting between them by hand is tedious and error-prone.

Type a number in any of the four common bases — binary, octal, decimal, or hexadecimal — and see it converted into all the others instantly, with optional prefixes for convenience.

Comment l’utiliser

Pick the input base

Choose binary, octal, decimal, or hexadecimal for what you are typing.
Type a number

The other three representations update live as you type.
Copy what you need

Each result has a copy button, with or without prefixes like 0x and 0b.

Exemples

The byte 255

The maximum value of a single byte in every base.

decimal 255

Résultat : binary 11111111 · octal 377 · hexadecimal FF

Questions fréquentes

What is a base?

Why does hex use letters?

Can I convert negative numbers?

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Last reviewed: 2026-09-25