Number Converters

Octal Converter

This octal converter moves values between octal and binary, decimal or hexadecimal. Octal still appears in Unix file permissions, so quick conversion is useful day to day.

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What this tool does

Converting base-8 numerals to and from other radices. This octal converter is free, works on desktop and mobile, and requires no sign-up.

Also useful for: binary number to octal, convert binary to octal converter, convert dec to octal, converting hex to octal, decimal to octal calculator, decimal to octal converter, decimal to octal number conversion, hex to octal.

Features

  • Octal to any base 2–36
  • Choose the target base
  • Arbitrary precision
  • Instant output

How to use it

  1. Enter an octal value
  2. Pick the base to convert to
  3. Copy the result

Examples

Permission bits 755 (octal)493 (decimal)

Common uses

  • Reading file permission modes
  • Legacy system work
  • Teaching octal

Good to know

  • Octal digits are 0–7 only

Frequently asked questions

Why does octal matter?

It maps cleanly to three-bit groups, which is why Unix permissions use it.

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