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Octal to Binary Converter
Enter a octal number to convert it to binary immediately. Paste multiple values (one per line) for bulk conversion. Arbitrary-precision math means even 128-bit values convert exactly.
Octal to Binary Converter
How to convert octal to binary
Octal (base 8) uses digits 0–7; each octal digit maps to exactly three bits, which is why Unix file permissions (e.g. 755) are written in octal. Binary (base 2) uses only the digits 0 and 1 and is how every value is ultimately stored in hardware.
Worked example converting 326:
- Expand by place value:
3×82 + 2×81 + 6×80= 214 in decimal. - Repeatedly divide 214 by 2 and read the remainders bottom-up to get 11010110.
- Result:
326(octal) =11010110(binary).
Accepted input formats
- Optional prefixes:
0b(binary),0o(octal),0x(hex). - Spaces, commas and underscores are ignored, so
1101_0110works. - A leading minus sign converts negative values (sign-magnitude, not two's complement).
- Hexadecimal is case-insensitive; output is upper-case.
Octal to Binary reference 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 |
| 40 | 100000 |
| 100 | 1000000 |
| 144 | 1100100 |
| 200 | 10000000 |
| 377 | 11111111 |
| 400 | 100000000 |
| 2000 | 10000000000 |
| 10000 | 1000000000000 |
| 177777 | 1111111111111111 |
Frequently asked questions
What is 326 in binary?
326 in octal equals 11010110 in binary.
Is there a size limit?
No practical limit. The converter uses JavaScript BigInt, so values with hundreds of digits convert exactly without rounding.
Is my data sent to a server?
No. The conversion runs entirely in your browser; nothing you type is uploaded.