Decimal to Binary Converter

Convert a decimal number to binary — and see it in octal and hexadecimal at the same time. Enter a number in any of the four bases and the other three update automatically.

Entering a Number In
All Bases Live
Binary (base 2)
Octal (base 8)
Decimal (base 10)
Hexadecimal (base 16)

This isn't the same as Text to Binary

Text to Binary encodes letters and symbols as character data — each character becomes an 8-bit (or more, for non-ASCII characters) binary block via ASCII or UTF-8. This tool instead converts a plain decimal number into the equivalent binary number using positional notation — 10 becomes 1010, a numeric value, not encoded text.

How decimal to binary conversion works

Repeatedly divide the decimal number by 2, keeping track of the remainder each time, until you reach 0. Reading the remainders from last to first gives the binary result.

Example: 10
10 ÷ 2 = 5 remainder 0 5 ÷ 2 = 2 remainder 1 2 ÷ 2 = 1 remainder 0 1 ÷ 2 = 0 remainder 1 Reading remainders bottom to top: 1010

Why this tool supports numbers larger than a calculator app usually can

A very large decimal number can exceed the range standard JavaScript number handling keeps exact — past a certain size, ordinary number arithmetic silently loses precision. This tool uses arbitrary-precision integer math internally specifically to avoid that, so even a very large number converts exactly, not approximately.

Frequently asked questions

How do you convert decimal to binary?

Repeatedly divide the number by 2, recording the remainder each time, until the result reaches 0. Reading the remainders in reverse order (last to first) gives the binary number. 10 in decimal becomes 1010 in binary this way.

What is 10 in binary?

1010. It's also 12 in octal and A in hexadecimal — all four represent the exact same number, just written in different bases.

What's the difference between Decimal to Binary and Text to Binary?

Decimal to Binary converts a number into the equivalent binary number. Text to Binary encodes letters and symbols as character data instead, turning each character into an 8-bit (or larger) binary block via ASCII or UTF-8. They use completely different logic despite both producing binary output.