Decimal to octal converter
Convert decimal to octal with BigInt and a successive division-by-8 table (quotient and remainder). Includes binary and hexadecimal and quick copy.
Base shortcuts
Decimal to Octal Calculator Online (Step-by-Step)
Convert decimal integers to octal instantly with BigInt, view the matching binary and hex values, and follow each successive division by 8.
Octal
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Normalized decimal
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Binary equivalent
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Hexadecimal
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Automatic divisions by 8
| Step | Dividend | Operation | Quotient | Remainder | Partial octal |
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How to convert decimal to octal
Split the sign from the magnitude and keep dividing the absolute value by 8: every remainder becomes an octal digit starting from the least significant.
- Normalize the input. Keep only one sign if present and remove spaces or comma separators.
- Work with the absolute value. Do the divisions on the unsigned number and keep the sign for later.
- Divide repeatedly by 8. Store quotient and remainder (0–7). While the quotient is above 0, keep dividing.
- Build the octal in reverse. Read the remainders from last to first and prepend “-” if the input was negative.
- Double-check. Rebuild the decimal with powers of 8 or compare against the binary and hex outputs.
Quick example: 478 ÷ 8 = 59 r 6, 59 ÷ 8 = 7 r 3, 7 ÷ 8 = 0 r 7 ⇒ 726₈.
0 → 0
7 → 7
8 → 10
64 → 100
255 → 377
1024 → 2000
FAQ
It works with integers (positive or negative). Spaces or commas are cleaned automatically before the conversion runs.
The sign is preserved. We convert the absolute value with divisions by 8 and, once the octal is built, prepend “-” when needed.
We display up to 2048 divisions to keep the page fast. The final octal result is still computed even if the table is truncated.
Copy buttons live on every output, and the grouping selector formats the octal to paste anywhere. Swap opens the inverse octal → decimal with the octal value passed in the URL.
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