How to convert decimal to binary
Divide the decimal number by 2 repeatedly, writing down each remainder. Read the remainders from the last to the first.
| Division | Quotient | Remainder |
|---|---|---|
| 156 ÷ 2 | 78 | 0 |
| 78 ÷ 2 | 39 | 0 |
| 39 ÷ 2 | 19 | 1 |
| 19 ÷ 2 | 9 | 1 |
| 9 ÷ 2 | 4 | 1 |
| 4 ÷ 2 | 2 | 0 |
| 2 ÷ 2 | 1 | 0 |
| 1 ÷ 2 | 0 | 1 |
Reading the remainders upward gives 156₁₀ = 10011100₍2₎.
About the number systems
Decimal
Base 10 is the everyday number system with digits 0–9; each position is worth ten times the one to its right.
Binary
Base 2 uses only the digits 0 and 1. Every value in a computer is ultimately stored as binary; each binary digit is a bit.
Decimal to binary table
| Decimal | Binary |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 10 |
| 3 | 11 |
| 4 | 100 |
| 5 | 101 |
| 6 | 110 |
| 7 | 111 |
| 8 | 1000 |
| 9 | 1001 |
| 10 | 1010 |
| 11 | 1011 |
| 12 | 1100 |
| 13 | 1101 |
| 14 | 1110 |
| 15 | 1111 |
| 16 | 10000 |
| 31 | 11111 |
| 32 | 100000 |
| 63 | 111111 |
| 64 | 1000000 |
| 100 | 1100100 |
| 127 | 1111111 |
| 128 | 10000000 |
| 255 | 11111111 |
| 256 | 100000000 |
| 1000 | 1111101000 |
| 1024 | 10000000000 |
| 4096 | 1000000000000 |
| 65535 | 1111111111111111 |
Frequently asked questions
How do I convert decimal to binary?
Divide the decimal number by 2 repeatedly, writing down each remainder. Read the remainders from the last to the first. Converting 156 to binary Division Quotient Remainder 156 ÷ 2 78 0 78 ÷ 2 39 0 39 ÷ 2 19 1 19 ÷ 2 9 1 9 ÷ 2 4 1 4 ÷ 2 2 0 2 ÷ 2 1 0 1 ÷ 2 0 1 Reading the remainders upward gives 156₁₀ = 10011100 ₍2₎.
What is 255 in binary?
255 (decimal) = 11111111 in binary.
Can I convert very large numbers?
Yes. The converter uses exact big-integer arithmetic, so there is no rounding even for long inputs.