Decimal to Binary Converter
Type a whole number below to convert it instantly to binary, with hexadecimal and octal shown as a bonus.
Decimal input
Converted result
How to convert decimal to binary
- Type a non-negative whole number into the box on the left.
- The binary equivalent appears instantly on the right, along with hexadecimal and octal.
- Copy the binary result with one click.
The divide-by-two method
Converting decimal to binary by hand uses repeated division by 2: divide the number by 2, note the remainder (0 or 1), then repeat with the quotient until it reaches 0. Reading the remainders from last to first gives the binary number. For example, 10 divided by 2 gives remainders 0, 1, 0, 1 (bottom to top), producing the binary number 1010.
| Decimal | Binary |
|---|---|
| 1 | 0001 |
| 4 | 0100 |
| 10 | 1010 |
| 15 | 1111 |
| 255 | 11111111 |
FAQ
Is this decimal to binary converter really free, with no sign-up?+
Yes. The tool runs entirely with JavaScript in your browser — there's no account, no API key, and no limit on how often you can use it.
How does decimal to binary conversion work?+
The decimal number is repeatedly divided by 2, and the remainders — read from last to first — form the binary digits. This tool performs that conversion automatically.
Can I convert negative numbers?+
This tool converts non-negative whole numbers. Negative numbers in binary depend on a chosen bit width and representation (like two's complement), which varies by context, so they're outside the scope of a simple converter like this one.
Is there a limit to how large a number I can convert?+
The converter handles integers up to JavaScript's safe integer limit (about 9 quadrillion) reliably, which covers every practical everyday use.
Can I also see the hexadecimal and octal equivalent?+
Yes, the result panel shows the binary, hexadecimal, and octal equivalents of your decimal input at the same time.
Tools for Number Conversion
How This Converter Works
Your value is converted live from decimal to binary, hexadecimal, and octal with JavaScript using the standard conversion formulas — nothing you enter is uploaded to a server or stored anywhere.
Last updated: August 28, 2026.
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