Number Base Converter

Convert between Binary, Octal, Decimal and Hexadecimal instantly

Type a number in any box — all other boxes update automatically

Binary (Base 2)

Digits: 0, 1

Octal (Base 8)

Digits: 0–7

Decimal (Base 10)

Digits: 0–9

Hexadecimal (Base 16)

Digits: 0–9, A–F

Quick Reference: 0–20 in all bases

Decimal	Binary	Octal	Hex

How to Convert Between Number Bases

Just type any number into the corresponding field and all other fields update automatically. No need to press a button.

Number Systems Explained

Base	Name	Digits Used	Common Use
2	Binary	0, 1	CPU instructions, bit flags, memory addressing
8	Octal	0–7	Unix file permissions (chmod 755)
10	Decimal	0–9	Everyday numbers
16	Hexadecimal	0–9, A–F	Colors (#FF5733), memory addresses, encoding

FAQ

Binary 1111 = 8+4+2+1 = 15 in decimal, and F in hexadecimal.

255 in binary is 11111111 — eight 1-bits. This is the maximum value of one byte and is commonly seen as 0xFF in hex or #FFFFFF in CSS colors.

One hex digit represents exactly 4 binary bits (a nibble). Two hex digits represent a full byte. This makes hex much more compact and readable than binary — e.g. FF vs 11111111.

Number Base Converter

How to Convert Between Number Bases

Number Systems Explained

FAQ

What is binary 1111 in decimal?

What is 255 in binary?

Why do programmers use hexadecimal?

Related Tools