How to convert octal to binary
Because 8 = 2^3, every octal digit corresponds to exactly 3 binary digits. Group the bits in sets of 3 from the right — or expand each digit into 3 bits.
Example
266₍8₎ = 1011 0110₂About the number systems
Octal
Base 8 uses digits 0–7. Each octal digit represents exactly three bits, which is why octal appears in Unix file permissions (e.g. 755).
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.
Octal to binary table
| Octal | Binary |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 10 |
| 3 | 11 |
| 4 | 100 |
| 5 | 101 |
| 6 | 110 |
| 7 | 111 |
| 10 | 1000 |
| 11 | 1001 |
| 12 | 1010 |
| 13 | 1011 |
| 14 | 1100 |
| 15 | 1101 |
| 16 | 1110 |
| 17 | 1111 |
| 20 | 10000 |
| 37 | 11111 |
| 40 | 100000 |
| 77 | 111111 |
| 100 | 1000000 |
| 144 | 1100100 |
| 177 | 1111111 |
| 200 | 10000000 |
| 377 | 11111111 |
| 400 | 100000000 |
| 1750 | 1111101000 |
| 2000 | 10000000000 |
| 10000 | 1000000000000 |
| 177777 | 1111111111111111 |
Frequently asked questions
How do I convert octal to binary?
Because 8 = 2^3, every octal digit corresponds to exactly 3 binary digits. Group the bits in sets of 3 from the right — or expand each digit into 3 bits. Example 266₍8₎ = 1011 0110₂
What is 755 in binary?
755 (octal) = 111101101 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.