Computer systems represent numbers in different bases depending on the context: binary (base 2) for low-level hardware operations, hexadecimal (base 16) for memory addresses and color codes, octal (base 8) for certain Unix permissions, and decimal (base 10) for everyday use. This number base converter instantly converts any number between binary, octal, decimal, and hexadecimal, showing all four representations simultaneously. It's an essential tool for programmers, computer science students, and anyone working with low-level data representations, color codes (like hex color #FF5733), or digital electronics. Simply enter your number and select its current base to see it converted to all other bases instantly.