Decimal to Binary
Convert decimal numbers to binary instantly. For example, 45 in decimal is 101101 in binary.
Decimal to Binary — quick reference
| Decimal | Binary |
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How to use the Decimal to Binary
- Type or paste your decimal value on the left.
- Read the binary result on the right — separate multiple values with spaces.
- Copy the result, or check the reference table below.
About the Decimal to Binary
This tool converts decimal numbers to binary. Decimal is base 10, written with the digits 0 through 9; binary is base 2, written with 0 and 1. Type a value on the left and the binary result appears instantly, and you can convert several values at once by separating them with spaces.
Worked example. Take 45 in decimal and divide repeatedly by 2, reading the remainders from bottom to top: 45 ÷ 2 = 22 remainder 1; 22 ÷ 2 = 11 remainder 0; 11 ÷ 2 = 5 remainder 1; 5 ÷ 2 = 2 remainder 1; 2 ÷ 2 = 1 remainder 0; 1 ÷ 2 = 0 remainder 1. Reading upward gives 101101.
Here you are going the other way — from the base-10 figures people write down to the bits a machine stores and manipulates, the form behind file sizes, bitmasks and low-level flags. The translation is exact by nature: a whole number in decimal and its binary twin are the same amount expressed differently, so nothing is rounded or dropped. The table further down offers more decimal-to-binary pairs to check yourself, and the whole conversion is handled in your browser, meaning nothing you type is ever uploaded. For the reverse direction use the binary to Decimal converter, or the all-in-one number base converter for arbitrary bases.
Frequently asked questions
What is 45 in decimal converted to binary?
45 in decimal equals 101101 in binary. You can confirm it with the worked example above, or by typing 45 into the converter.
Is this decimal to binary conversion exact?
Yes. Converting a whole number between bases changes only how it is written, not its value, so there is no rounding. 45 and 101101 are the same quantity expressed in base 10 and base 2.
Can I convert more than one decimal value at once?
Yes. Separate each decimal value with a space and every one is converted to binary on its own, in order.
Is my data uploaded anywhere?
No. The conversion runs entirely in your browser with JavaScript; nothing you type is sent to a server.