Convert numbers between binary (base 2), octal (base 8), decimal (base 10), and hexadecimal (base 16).
A number base (or radix) determines how many unique digits are used. Decimal (base 10) uses 0-9. Binary (base 2) uses 0-1. Hexadecimal (base 16) uses 0-9 and A-F. Octal (base 8) uses 0-7.
Hexadecimal is compact — each hex digit represents 4 bits, so a byte (8 bits) is just 2 hex digits. This makes it ideal for memory addresses, color codes, and binary data inspection.