Decimal to Binary Converter
Type a decimal number of any length to see it in binary, with every step of the working.
Decimal to binary table
| Decimal | Binary |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 10 |
| 3 | 11 |
| 4 | 100 |
| 5 | 101 |
| 7 | 111 |
| 8 | 1000 |
| 10 | 1010 |
| 15 | 1111 |
| 16 | 10000 |
| 32 | 100000 |
| 64 | 1000000 |
| 100 | 1100100 |
| 127 | 1111111 |
| 128 | 10000000 |
| 255 | 11111111 |
| 256 | 100000000 |
| 1000 | 1111101000 |
| 1024 | 10000000000 |
Worked examples
10 in binary
10 (decimal)
1010 (binary)
Decimal value 10.
255 in binary
255 (decimal)
11111111 (binary)
Decimal value 255.
2026 in binary
2026 (decimal)
11111101010 (binary)
Decimal value 2026.
About Decimal to Binary Converter
This converter turns decimal numbers into binary and shows how. To convert decimal to binary, divide the number by 2 again and again, writing down each remainder, then read the remainders from last to first. For example, 10 in decimal is 1010 in binary, and 2026 is 11111101010.
Decimal is the base 10 system we count in every day, with place values of ones, tens, hundreds and so on. Binary is the language of computers: every value in memory is a pattern of bits, each one a 0 or a 1. Numbers of any length are converted exactly, because the tool works with whole numbers digit by digit instead of rounding.
How to use Decimal to Binary Converter
- Type or paste a decimal number into the first box. Spaces, underscores and prefixes such as 0x are ignored.
- Read the binary result straight away in the second box, grouped for easier reading if you leave the box ticked.
- Look at the working table to see each step of the method.
- Copy the result, or use the swap button to convert binary back to decimal.
Common uses
- Reading or setting bit flags and permissions in software
- Working out subnet masks and IP address ranges
- Computer science and GCSE or A level homework
- Checking how a number is stored in memory
Frequently asked questions
How do I convert decimal to binary by hand?
Divide the number by 2 again and again, writing down each remainder, then read the remainders from last to first. The working table on this page shows exactly these steps for the number you type.
What is 255 in binary?
255 in decimal is 11111111 in binary. In decimal it is 255, the largest number that fits in one byte.
What is 2026 in binary?
2026 in decimal is 11111101010 in binary.
Can it convert very large numbers?
Yes. Whole numbers with up to 4,096 digits are converted exactly. The working table shows the first rows when a number is very long.
Does it handle fractions or negative numbers?
Negative whole numbers are converted with their minus sign kept. Fractions are not supported, because many fractions that end in one base repeat for ever in another.