Octal Converter
Enter an octal (base-8) number and get its decimal, binary and hexadecimal values. It is useful for Unix permission modes, legacy systems and number-system exercises.
How to use the Octal Converter
- Type an octal number using the digits 0–7.
- Read the decimal, binary and hexadecimal results.
- Look at the binary grouping to see the permission bits.
- Copy any result.
Features
- Digit validation for base 8
- Optional 0o prefix
- Exact conversion for large values
- All four bases displayed together
Benefits
- Understand chmod values like 755 and 644
- Convert values from older documentation
- Practise number base conversions
Frequently asked questions
What does chmod 755 mean in binary?
755 in octal is 111 101 101 in binary: read, write and execute for the owner, and read and execute for group and others.
Why are 8 and 9 rejected?
Octal only uses the digits 0 to 7. The tool tells you which digit is invalid.
How is octal related to binary?
Each octal digit corresponds to exactly three binary bits, which makes conversion between them straightforward.
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