Conversions

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Decimal to Octal Converter.

Convert a non-negative integer from base 10 to base 8.

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Use Cases

Programming and Digital Systems

Convert decimal numbers to octal for use in computer programming, file permissions (Unix), or digital electronics where octal representation is preferred.

Example: Convert decimal 64 to octal 100.

Educational Learning

Help students understand number base conversions by quickly checking their manual calculations of decimal to octal or octal to decimal.

Example: Verify that decimal 255 equals octal 377.

Frequently Asked Questions

How do I convert decimal to octal using this calculator?
Select 'DECIMAL' in the 'Convert from' dropdown and 'OCTAL' in the 'Convert to' dropdown. Enter your decimal number in the input field and click convert. The tool will display the octal equivalent.
Can I convert octal back to decimal with this tool?
Yes. Choose 'OCTAL' in 'Convert from' and 'DECIMAL' in 'Convert to', then enter the octal number. The calculator will return its decimal value.
What is the octal number system?
Octal is a base-8 number system using digits 0-7. Each octal digit represents three binary digits. It's often used in computing as a compact representation of binary numbers.

Tips & Common Mistakes

Tips

  • Ensure your input is a non-negative integer. The calculator does not handle negative numbers or decimals.
  • Double-check that you have selected the correct 'Convert from' and 'Convert to' options to avoid reversed conversions.
  • For large numbers, the octal result may have more digits than the decimal input. This is normal.
  • Use the tool to verify manual conversions, especially when learning the division-remainder method.

Common Mistakes to Avoid

  • Selecting the wrong conversion direction, e.g., choosing 'OCTAL' as 'Convert from' when you meant to convert from decimal.
  • Entering a number with digits 8 or 9 when converting from octal, which are invalid in base 8.
  • Assuming the result is in decimal when converting from decimal to octal; the output is in octal, so it may look different.

Last updated: August 13, 2026