Decimal to Binary
Convert a whole number from decimal (base-10) to binary (base-2).
About the Decimal to Binary converter
This tool converts an everyday base-10 number into binary, the base-2 form computers use. It works by repeatedly dividing by two and reading the remainders, so 13 becomes 1101. It is great for learning positional number systems, working through electronics and logic problems, and preparing bit patterns for masks or flags.
How to use it
- Enter a decimal whole number in the input.
- The binary equivalent appears immediately.
- Copy the bits for a circuit, bit mask, or worksheet.
A common use is building a bitmask from a familiar number or checking which bits are set in a value. The converter treats the input as an unsigned whole number and handles very large values exactly, so 64-bit numbers convert without rounding. It expects whole numbers, not fractions, and does not produce a sign bit. Everything runs in your browser, so the numbers you enter are never uploaded.
Frequently asked questions
How does decimal convert to binary?
The number is repeatedly divided by two and the remainders, read from last to first, form the binary digits. For example 13 yields 1101.
Can it convert decimal fractions?
No. This converter is built for whole numbers, so round or truncate to an integer before converting.
Does it produce a fixed-width result or pad with zeros?
It returns the minimal binary representation without leading zeros. Add padding yourself if you need a fixed byte or word width.
Is the number I enter uploaded?
No. The conversion runs entirely in your browser, so your input stays on your device.