Number Base Converter
Convert numbers between binary, octal, decimal and hexadecimal.
255 in decimal is FF in hex and 11111111 in binary — the numbers behind every colour code (#FF5733) and IP address you’ve seen. Programmers live in hex because each digit maps neatly to 4 bits.
How to use the number base converter
- Enter a number.
- Pick which base it’s in.
- See binary, octal, decimal and hex together.
Number Base Converter — FAQs
What is hexadecimal used for?
Colour codes (#FF0000), memory addresses, and compact binary representation — each hex digit is exactly 4 bits.
How do I convert binary to decimal by hand?
Sum the powers of 2 where bits are 1: 1011 = 8+0+2+1 = 11.
Why do programmers like hex?
It’s compact and maps cleanly to binary — two hex digits make one byte (0–255).
What are invalid digits?
Each base limits its digits: binary only 0–1, octal 0–7, decimal 0–9, hex 0–9 plus A–F.
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