Number Base Converter

Number Base Converter

Switching a value between binary, octal, decimal, and hexadecimal is a constant task in low-level and systems work, from reading memory addresses to setting bit flags and color values. This number base converter takes a number in any of those bases and shows its equivalent in all the others at once, so you don't have to reach for a calculator or mental math.

How it works

The conversion happens locally in your browser. Enter a value and choose its base, and the tool parses it and re-encodes it into binary, octal, decimal, and hexadecimal on your machine, updating every field as you type. Because it's plain client-side JavaScript, there's nothing to install, nothing is uploaded, and it keeps working offline once loaded.

Common use cases

• Decode a hex memory address or opcode into decimal.
• Work out bitmask and flag values in binary.
• Translate permission or color values between bases.
• Check homework or interview answers quickly.

Need to go further? Convert text to its binary representation with Text to Binary, translate hex color codes with the Color Converter, or handle Roman numerals using the Roman Numeral Converter.

Private by design

Whatever you enter stays in your browser — no upload, no account, no tracking. The converter is completely free and runs on any modern browser, including mobile, so you can crunch bases anywhere without sending a single value to a server.