Purpose: Convert a value between binary, octal, decimal and hexadecimal - type in any field and the rest update live.
Number Base Converter
The Number Base Converter translates values between binary, octal, decimal, and hexadecimal - the number systems that underpin computing and digital electronics.
Why base conversion matters
Computers store everything in binary (base 2). Programmers use hexadecimal (base 16) as a compact way to write binary - each hex digit maps to exactly four bits - which is why colours (#FF8800), memory addresses, and byte values are written in hex. Octal (base 8) still appears in Unix file permissions.
How the conversion works
Enter a value in any base and the tool converts it to the others. For example decimal 255 is 11111111 in binary, 377 in octal, and FF in hexadecimal. It validates your input, so entering a digit that is not allowed in the chosen base (like a 2 in binary) is flagged immediately.
Frequently Asked Questions
Why do programmers use hexadecimal?
Hex is a compact, human-readable stand-in for binary: each hex digit equals four binary bits, so long bit strings become short and easy to read.
What is decimal 255 in hex and binary?
255 is FF in hexadecimal and 11111111 in binary - the largest value that fits in a single byte.
Does it validate the digits I enter?
Yes. If you type a digit that is not valid for the selected base, such as a 9 in octal, the tool flags it.
Which bases are supported?
Binary (base 2), octal (base 8), decimal (base 10), and hexadecimal (base 16), converting freely between all four.
Related Calculators Tools
Browse all Calculators tools →
Privacy-first: client-side tools process your input in your browser. Free to use, no sign-up. See our Privacy Policy and Disclaimer.