Decimal to Binary Converter
Convert any decimal number to binary instantly — pick a bit length, see every division step. Free, fast, no sign-up.
Enter a whole number (digits only).
Bit length:
Binary result
Step-by-step
| Division | Quotient | Remainder |
|---|
Read the remainders bottom → top.
How to convert decimal to binary
- Divide the decimal number by 2 and write down the remainder (0 or 1).
- Divide the quotient by 2 and write down the new remainder.
- Repeat until the quotient is 0, then read the remainders from bottom to top.
Example: 13 → 13÷2=6 r1, 6÷2=3 r0, 3÷2=1 r1, 1÷2=0 r1 → 1101.
Quick reference table
| Decimal | Binary |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 10 |
| 3 | 11 |
| 4 | 100 |
| 5 | 101 |
| 8 | 1000 |
| 10 | 1010 |
| 15 | 1111 |
| 16 | 10000 |
| 100 | 1100100 |
| 255 | 11111111 |
Frequently asked questions
How do I convert decimal to binary?
Repeatedly divide by 2, record each remainder, and read the remainders bottom-to-top. The converter above shows every step.
What is 10 in binary?
10 in decimal equals 1010 in binary.
How do I convert decimal to 8-bit binary?
Convert as normal, then pad with leading zeros to 8 digits — e.g. 10 becomes 00001010. Use the bit-length selector above.
Need the reverse? Try our binary to decimal converter.