Number Base Converter | A free, easy online tool

Number bases

Binary

Octal

Decimal

Hexadecimal

Type any value in any field. Other bases update live.

Encode URL HTML Entities Base64 Encode Hash Number Base

How it Works

Type a number in any field — Binary, Octal, Decimal, or Hexadecimal — and the other three update in real time. Internally everything is stored as a JavaScript BigInt, so values larger than 2⁵³ are handled correctly without losing precision.

What's Accepted

Binary: digits 0–1, optional 0b prefix.
Octal: digits 0–7, optional 0o prefix.
Decimal: digits 0–9.
Hex: digits 0–9 and a–f, optional 0x prefix.

Common Use Cases

Reading hex dumps: Convert a memory address or byte value to decimal.
Bit-flag work: See which bits are set in a binary representation.
Permission masks: Convert Unix octal modes (e.g. 755) into binary.
Embedded development: Move between number bases for register values, op-codes, or addresses.

Privacy and Security

All conversions run locally in your browser. Nothing is sent to a server, logged, or stored.

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