Number Base Converter

Number Base Converter — Binary, Octal, Decimal, Hex

The Number Base Converter from facilita.tools converts values between binary (base 2), octal (base 8), decimal (base 10), and hexadecimal (base 16) — instantly and for free. Enter any number, select its current base, choose the target base, and see the result immediately along with the value represented in all four numbering systems simultaneously. The converter supports very large numbers using BigInt arithmetic, so you can work with values far beyond the standard 32-bit or 64-bit integer limits. Binary is used in digital electronics and computer memory, where everything is represented as sequences of 0s and 1s. Octal (base 8) simplifies binary representation and is commonly used in Unix file permissions (e.g., chmod 755). Decimal is the standard human numbering system. Hexadecimal (base 16) is widely used in programming, web colors (e.g., #FF5733), memory addresses, MAC addresses, and cryptographic hashes. This tool is essential for programmers, computer science students, network engineers, and electronics hobbyists. Invalid input is detected automatically with clear error feedback so you always know exactly what went wrong. Click on any value in the results table to copy it instantly. Binary output is formatted in 4-bit groups for readability, and decimal output includes thousand separators. All processing runs locally in your browser using JavaScript — no server, no registration,