Unit Converters
Number Base Converter
Convert numbers between binary, octal, decimal, and hex.
FreeNo sign-upWorks in your browser
Binary (base 2)
11111111
Octal (base 8)
377
Decimal (base 10)
255
Hexadecimal (base 16)
FF
About the Number Base Converter
Convert numbers between binary, octal, decimal, and hexadecimal free — binary to decimal, decimal to hex, hex to binary, and every other direction, updating live as you type. A staple for programmers, computer science students, and anyone working with bit flags, memory addresses, color codes, or file permissions.
How to use the Number Base Converter
- 1Enter a value and select its input base.
- 2See it converted to all common bases.
- 3Copy the representation you need.
Frequently asked questions
Which bases are supported?
Binary (2), octal (8), decimal (10), and hexadecimal (16).
Can it handle large numbers?
It converts standard integers reliably; extremely large values may exceed JavaScript's safe integer range.
What is FF in decimal?
255 — hexadecimal FF is 15×16 + 15. It's the max value of one byte, which is why RGB colors go 0–255 per channel.