Decimal to Binary Converter

Convert decimal (base-10) numbers to binary (base-2) format. Also see hexadecimal and octal equivalents.

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Enter a decimal number to convert

Frequently Asked Questions

How do you convert decimal to binary?

Repeatedly divide the decimal number by 2 and collect the remainders from bottom to top. For 13: 13÷2=6r1, 6÷2=3r0, 3÷2=1r1, 1÷2=0r1 → binary is 1101.

How are negative numbers represented in binary?

Negative integers are typically represented using two's complement in computing. The most significant bit is the sign bit (1 = negative). -1 in 8-bit two's complement is 11111111.

What is hexadecimal and how does it relate to binary?

Hexadecimal is base-16 (digits 0–9 and A–F). One hex digit represents exactly 4 binary bits, making it a compact way to write binary values. 0xFF = 11111111 in binary = 255 in decimal.