# Octal Converter

> Octal converter: convert octal numbers to decimal, binary, and hexadecimal, or back the other way, instantly and accurately. Free, private, in-browser.

- **Canonical URL:** https://boringtoolskit.com/octal-converter/
- **Category:** Converters
- **Evidence level:** authored-methodology
- **Reviewed:** 2026-09-20
- **Last verified:** 2026-10-12
- **Privacy:** Inputs and results stay in this browser unless the page clearly labels an external request.

## How it works

Octal (base 8) = the decimal value regrouped into powers of 8: divide by 8 repeatedly and read the remainders upward. The same value is also shown in binary (base 2) and hexadecimal (base 16).

## Assumptions

- Inputs are treated as exact decimal values.
- Standard (not historical or survey) unit definitions are used.
- The calculation uses the factors at the precision shown in the formula panel; rounding beyond that is display-only and adds no accuracy.

## Common questions

### Is an octal conversion exact?

Yes. Base conversion only regroups the same quantity, so it does not round. The limit is the input: whole numbers from 0 to 2^53 convert exactly; beyond that JavaScript cannot represent every integer exactly and the tool rejects it.

## Sources

- [ISO/IEC 9899 (C) - octal integer constants](https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3096.pdf)

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