Number Base Converter

Number Base Converter instantly converts any whole number between binary, octal, decimal and hexadecimal. Type a value, pick its base, and see all four representations at once. All processing happens locally in your browser, and nothing is sent to a server.

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About Number Base Conversion

Number base (or radix) conversion expresses the same value in different numeral systems. Binary (base 2) uses 0-1, octal (base 8) uses 0-7, decimal (base 10) uses 0-9, and hexadecimal (base 16) uses 0-9 and a-f.

This converter uses arbitrary-precision integers, so very large numbers convert accurately without rounding errors.

Base conversion shows up everywhere in programming: memory addresses and colour codes in hexadecimal, file permissions in octal, and bitmasks or flags in binary. Hexadecimal stays popular because two hex digits map neatly onto one byte, which makes raw data compact and easy to scan.

Frequently Asked Questions

Is this number base converter free and private?
Yes. It is completely free and runs entirely in your browser, so the numbers you convert are never uploaded or stored on any server.
How large a number can it convert?
It uses arbitrary-precision (BigInt) arithmetic, so it converts very large integers between binary, octal, decimal and hexadecimal without rounding or overflow errors.
Can it convert negative numbers or hex with a 0x prefix?
Yes. Negative values are supported, and common prefixes like 0x, 0b and 0o are accepted; spaces and underscores in the input are ignored.