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Octal Converter

Convert octal numbers to decimal, binary and hex — and decode Unix file permissions like 755 into rwx form.

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About the Octal Converter

Octal (base 8) is used mainly for Unix file permissions and some legacy systems. Convert any octal number to other bases, and for three- or four-digit values see the permission string — 755 becomes rwxr-xr-x.

How to use it

  1. Enter a number and choose its base (octal by default).
  2. Read the conversions and permission string.

Good to know

  • Arbitrary-size integers are converted exactly.

Frequently asked questions

What does chmod 644 mean?

Owner read/write, group and others read-only (rw-r--r--).

Why is octal used for permissions?

Each octal digit maps exactly to three bits: read, write and execute.

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