Number Base Converter
Enter a number in binary, octal, decimal, or hex, and read it in all four bases at once.
How it works
A number's value never changes — only how it's written. Decimal 255 is 11111111 in binary, 377 in octal, and FF in hex. Pick the base you're starting from and the tool reads your value in that base, then re-expresses it in the other three.
Hexadecimal is a favorite in programming because each hex digit maps neatly to four binary bits, so FF is exactly one byte. That's why colors, memory addresses, and byte values are so often written in hex.
If a digit doesn't belong to the base you chose — say a 2 in a binary number, or a G in hex — the value is invalid and the results clear, so you always know the input is clean.
Frequently asked questions
What is hexadecimal used for?
Hex is a compact way to write binary. Each digit covers four bits, so a byte is two hex digits. Colors (#FF8800), memory addresses, and byte values are commonly shown in hex.
How do I convert binary to decimal?
Each binary digit represents a power of two. The tool does it for you — set the base to binary, type the digits, and read the decimal row. For example, 1010 in binary is 10 in decimal.
Why does my input show no result?
The value probably contains a digit that isn't valid for the chosen base, like a 9 in an octal number. Fix the digit or switch to a base that allows it and the results reappear.