Binary / Decimal / Hex / Octal Converter
Type a value into any one of the four fields below — Binary, Decimal, Hexadecimal or Octal — and the other three update instantly. Perfect for developers, students and networking work.
How to Use the Number Base Converter
- Click into any of the four fields — Binary, Decimal, Hex or Octal.
- Type a valid value for that number base.
- The other three fields update live to show the same value in their respective base.
- If you type an invalid character for the selected base, a friendly warning appears instead of a wrong result.
Why Use This Tool?
How does the conversion actually work?
Whatever field you edit is first parsed using JavaScript's parseInt(value, base) for that field's base (2 for binary, 10 for decimal, 16 for hex, 8 for octal), turning it into a single underlying integer. That integer is then converted back into the other three bases using .toString(base), so all four fields always represent exactly the same number.
What characters are valid in each base?
Binary only allows 0 and 1. Octal allows digits 0–7. Decimal allows digits 0–9. Hexadecimal allows digits 0–9 plus letters A–F (either case) representing values 10–15. Typing any other character in a field triggers a clear inline warning rather than a silently wrong conversion.
Who uses binary/hex/octal conversion?
Software developers debugging bitwise operations and memory addresses, network engineers working with subnet masks and MAC addresses, students learning computer science fundamentals, and anyone working with color codes or file permissions (which are often shown in octal, like 755) all rely on quick, accurate base conversions.
Is there a limit to how large a number I can convert?
This tool uses standard JavaScript integers, which reliably handle whole numbers up to about 9 quadrillion (2^53). That covers virtually every practical use case for base conversion in programming, networking and education.