TOOLConvert between number bases
Enter a value in decimal, binary, octal or hexadecimal and the other three update instantly. It's the fast reference for reading a hex color, a binary flag, a memory address or any low-level value — edit whichever field you have, and read the rest.
What the bases mean
- Binary (base 2) — only 0 and 1, the language computers actually store.
- Octal (base 8) — digits 0-7, groups binary in threes; seen in Unix file permissions.
- Decimal (base 10) — the everyday numbers people read.
- Hexadecimal (base 16) — 0-9 then A-F; a compact stand-in for binary, since each hex digit is exactly 4 bits.
Quick example
Frequently asked questions
How do I convert decimal to binary?
Enter your decimal number and read the binary field. The tool repeatedly divides by 2 internally; for example, 255 in decimal is 11111111 in binary.
What base is hexadecimal?
Hexadecimal is base 16. It uses the digits 0-9 and the letters A-F for values 10 to 15, so it can represent a byte (0-255) in just two characters, like FF for 255.
Why do programmers use different number bases?
Binary maps directly to how computers store data, hexadecimal is a compact way to write binary (each hex digit is 4 bits), and octal groups bits in threes. Decimal is what people read, so converting between them is an everyday task in low-level work.