Decimal to Binary Converter
Convert decimal numbers to binary (base 2) instantly. Visual bit grouping for easy reading.
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How to Convert Decimal to Binary
Repeatedly divide by 2 and record the remainders:
- Divide the decimal number by 2
- Record the remainder (0 or 1)
- Divide the quotient by 2 again
- Repeat until the quotient is 0
- Read the remainders in reverse order
Example: Convert 13 to binary:
- 13 ÷ 2 = 6 remainder 1
- 6 ÷ 2 = 3 remainder 0
- 3 ÷ 2 = 1 remainder 1
- 1 ÷ 2 = 0 remainder 1
- Result: 1101 (reading remainders in reverse)
Code Examples
const decimal = 10;
const binary = decimal.toString(2); // "1010"
const padded = decimal.toString(2).padStart(8, '0'); // "00001010"Frequently Asked Questions
How do I convert decimal to binary?
Divide the decimal number by 2 repeatedly, noting the remainders. Read the remainders in reverse order. For example, 10 ÷ 2 = 5r0, 5 ÷ 2 = 2r1, 2 ÷ 2 = 1r0, 1 ÷ 2 = 0r1, giving 1010.
How many bits do I need for a number?
The number of bits needed is ⌈log₂(n+1)⌉. Common sizes: 8 bits (0-255), 16 bits (0-65535), 32 bits (0-4.29B). Negative numbers require an extra sign bit.
What's the 0b prefix?
The 0b prefix indicates a binary number in languages like JavaScript, Python, and Rust. For example, 0b1010 equals decimal 10. It helps distinguish binary from decimal literals.