Binary, Hex & Decimal Explained - How to Convert

🔢Free Binary / Hex / Decimal Converter
Convert between binary, hexadecimal, decimal and octal.Open tool →

Decimal (base 10)

Each position is worth 10 times the one to its right: 352 = 3×100 + 5×10 + 2×1.

Binary (base 2)

Each position is worth twice the one to its right: 1011 = 1×8 + 0×4 + 1×2 + 1×1 = 11. Eight binary digits (a byte) hold 0-255.

Hexadecimal (base 16)

Uses 0-9 then A-F for 10-15. Each hex digit equals exactly 4 binary digits, so a byte is two hex digits: 255 = FF, 16 = 10. That's why colours are written like #19C6A6.

Convert instantly

Type a number in any box of the Binary / Hex / Decimal Converter and the others update – it handles very large numbers and negatives.

Frequently asked questions

What is 255 in binary?

11111111.

Why do computers use binary?

Circuits reliably represent two states: on and off.

What is octal used for?

Mainly Unix file permissions like 755.