Decimal to Binary
Turn Decimal numbers into Binary in your browser. Every digit is converted exactly, even for very long values, and nothing is sent to a server.
Free Runs locally No signup
Binary
11111111Octal
377Decimal
255Hexadecimal
FFSpaces and underscores are ignored; 0b, 0o and 0x prefixes are supported.
Common conversions
| Decimal | Binary |
|---|---|
| 1 | 1 |
| 2 | 10 |
| 4 | 100 |
| 8 | 1000 |
| 10 | 1010 |
| 16 | 10000 |
| 255 | 11111111 |
Leading zeros are dropped; longer values follow the same digit weights.
Frequently asked questions
How do I convert Decimal to Binary?
Each Decimal digit is multiplied by its place value, then the total is written using Binary digits. The table above shows the pattern for small values.
Can I convert fractions?
No. This converter works with unsigned integers only. Convert the integer part first and handle the fraction separately.
How large can the numbers be?
Up to 200 characters, which covers values far beyond 64-bit range. Precision stays exact because the conversion uses big integers.
Related conversions
Binary to Decimal Decimal to Hexadecimal Decimal to Octal Hexadecimal to Decimal Octal to Decimal Binary to Hexadecimal
Open the full unit converter