Number Base Converter
Convert between decimal, binary, hexadecimal, and octal. All in your browser.
Try it with this example
Enter 255 and convert to binary (11111111) or hex (FF). Bidirectional conversion.
What is this tool?
Computers store numbers in binary; programmers often use hexadecimal for compact notation. The Number Base Converter converts between decimal, binary, hexadecimal, and octal. Enter 255 and see 11111111 in binary, FF in hex, and 377 in octal. Enter FF and get 255 in decimal. Bidirectional conversion in any supported base. Essential for low-level programming, debugging, and learning how number systems work.
Decimal is base 10 (0–9); binary is base 2 (0–1); hexadecimal is base 16 (0–9, A–F); octal is base 8 (0–7). Programmers use hex for memory addresses, color codes (#FF5733), and byte dumps. Binary appears in bitwise operations and hardware specs. Octal is less common but still used in file permissions (chmod 755). The tool handles positive integers; negative numbers and floating point would require additional logic.
Enter a number in one base and convert to all others. Or enter in the target base and get decimal. Large numbers are supported within JavaScript's safe integer range. Use it when reading hex dumps, when converting color values, when learning binary arithmetic, or when debugging "why is this bit flag not working?"—often a base conversion clarifies the issue.
All conversion runs in your browser. No server, no API. The tool is for quick reference; for scripting, use your language's built-in conversion (e.g. parseInt in JavaScript, int() in Python with a base argument). This tool fills the gap when you need a one-off conversion without writing code.
Bookmark it for programming, electronics, and CS education.