How to convert Octal to Decimal
Octal is a positional system with place values that are powers of 8. To convert to decimal, multiply each digit by its place value — 8⁰ for the rightmost digit, 8¹ for the next, and so on — then add everything up.
Worked example
Convert 725 (octal) to decimal:
- Write out the place values:
725= 7×64 + 2×8 + 5×1 - Add them up:
469
So 725 in octal is 469 in decimal.
Octal to Decimal conversion table
| Octal | Decimal |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 2 |
| 3 | 3 |
| 4 | 4 |
| 5 | 5 |
| 6 | 6 |
| 7 | 7 |
| 10 | 8 |
| 11 | 9 |
| 12 | 10 |
| 13 | 11 |
| 14 | 12 |
| 15 | 13 |
| 16 | 14 |
| 17 | 15 |
Frequently asked questions
- Can this handle numbers larger than 64 bits?
- Yes. Conversion runs on arbitrary-precision integers, so numbers of any length convert exactly. Many online converters silently lose precision above 2⁵³ (about 16 decimal digits) — this one doesn't.
- How do I convert negative numbers?
- A leading minus sign works in every base. For the bit-pattern view programmers usually want, switch the mode to two's complement at 8, 16, 32, or 64 bits — then binary, octal, and hex show the bit pattern while decimal shows the signed value.
- Can I convert the other way, or to other bases?
- Use the Decimal to Octal converter, or just change the From/To dropdowns above — every common base is shown at once anyway, and a Text mode converts ASCII to bytes and back.
Need arithmetic rather than conversion — adding hex numbers, shifting bits, masking? Use the programmer's calculator.