Number Base Converter | A free, easy online tool

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.

Encoding Tools

URL Format Encoder - Encode any text into URL friendly characters
HTML Entity Encoder - Convert special characters to HTML entities for safe display in web pages
Base64 Encoder - Encode text to Base64 format. Perfect for URLs, emails, and APIs.
Hash Generator - Generate MD5, SHA-1, SHA-256, SHA-384, and SHA-512 hashes from any text in your browser.