Number Converter
Convert numbers between Binary, Octal, Decimal, and Hexadecimal.
What the Number Converter does
This tool converts a whole number between the four number bases programmers use most: binary (base 2), octal (base 8), decimal (base 10), and hexadecimal (base 16). Type a value into any one of the fields and the other three update instantly to show the same number in every base. A quick-reference panel also lists all four representations together with their conventional prefixes (0b, 0o, and 0x).
It is useful for developers, students, and anyone working with low-level data such as bitmasks, color codes, memory addresses, file permissions, or byte values, where switching between hex, binary, and decimal is a constant need.
How to use it
Pick the base you want to start from and type your number into that field. As you type, the tool parses the value and immediately fills in the equivalent decimal, binary, octal, and hexadecimal forms. You can include the usual prefix (such as 0x for hex) or leave it out; the tool strips a leading 0b, 0o, or 0x automatically before converting.
Each field has a copy button so you can grab a single representation in one click. If you enter a character that is not valid for the chosen base, for example a digit 2 in a binary field or a letter G in hex, the tool clears the other fields and shows an Invalid value message until you correct it.
Tips and notes
Hexadecimal output is shown in uppercase for readability, and the converter is case-insensitive on input, so 0xff and 0xFF are treated the same. The tool works with whole numbers; fractional or decimal-point values are not supported.
Everything runs in your browser with no network requests, so conversions are instant and nothing you enter is sent anywhere.