About This Converter
Convert any decimal (base 10) number to binary (base 2) using the repeated division method. Enter a number like 25 and instantly see the binary result (11001) with each division step shown. Perfect for computer science homework, exam practice, and understanding how computers store integers.
Worked Examples
Decimal: 13 → Binary: 1101
13÷2=6 R1, 6÷2=3 R0, 3÷2=1 R1, 1÷2=0 R1 → read bottom-up: 1101
Decimal: 255 → Binary: 11111111
Eight consecutive 1-bits — maximum value for one byte
Decimal: 100 → Binary: 1100100
100 in binary is 1100100 (7 bits needed)
Need More Bases?
For full multi-base conversion (binary, octal, decimal, and hex all at once), use our Number System Converter — it shows all four representations simultaneously with complete step-by-step working.