Decimal to Binary Calculator
Convert a decimal (base 10) number to binary (base 2).
- Free to use
- Accurate results
- No registration required
- Works on all devices
Enter a decimal number to convert it to binary.
A non-negative whole number.
Your result
11111111
Binary
AI explanation
Formula
Repeated division by 2, reading the remainders from bottom to topWorked example
255 to binary
| Field | Value |
|---|---|
| Decimal number | 255 |
| Binary | 11111111 |
Assumptions
- Only non-negative whole numbers are supported.
Frequently asked questions
How do I convert decimal to binary by hand?
Repeatedly divide the decimal number by 2, recording the remainder (0 or 1) each time. Reading the remainders from the last division to the first gives the binary result.
How many binary digits does a decimal number need?
It depends on the value — for example, decimal 255 needs 8 binary digits (11111111), the largest value representable in a single byte.
What about the reverse conversion?
Use the Binary to Decimal Calculator to convert a binary number back to decimal.