Convert Octal to Decimal
Enter a Octal number to get its Decimal value — plus every other common base. Exact even for huge integers, all in your browser.
That's not a valid number for the selected base.
- Binary base 2
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- Octal base 8
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- Decimal base 10
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- Hexadecimal base 16
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Worked example
377 in Octal converts to 255 in Decimal. The converter above is pre-filled with this value — edit it to see the result update live.
Octal to Decimal reference table
| Decimal | Octal | Decimal |
|---|---|---|
| 10 | 12 | 10 |
| 16 | 20 | 16 |
| 32 | 40 | 32 |
| 100 | 144 | 100 |
| 255 | 377 | 255 |
Common uses
Often needed to interpret Unix file permissions or read data from legacy systems that output in base 8.
Related conversions
Need another base? The full number base converter handles any base from 2 to 36 and converts them all simultaneously.
Frequently asked questions
How do I convert Octal to Decimal?
Enter your Octal value into the converter above and it shows the Decimal equivalent — along with every other base — instantly. For example, 377 in Octal becomes 255 in Decimal.
Can it handle very large numbers?
Yes. The converter uses arbitrary-precision math, so even numbers with hundreds of digits convert exactly without the rounding errors you'd get from a normal calculator.
Is my data sent to a server?
No. Every conversion runs locally in your browser using standard JavaScript BigInt math, so nothing you enter is uploaded.