What is an octal number?

An octal number uses base 8, meaning it has eight digits: 0 through 7. Each octal digit represents exactly three binary bits, making octal a compact shorthand for binary values.

How do you convert decimal to octal?

Divide the decimal number by 8 and record the remainder. Divide the quotient by 8 again and record the remainder. Repeat until the quotient is 0. Reading the remainders from last to first gives the octal number.

Does this tool handle negative numbers?

Yes. The converter strips the minus sign, converts the absolute value to octal, then prepends the minus sign to the result.

Is there a size limit on the input?

The tool uses JavaScript's BigInt, so it handles arbitrarily large integers without floating-point rounding errors.

Decimal to Octal Converter

Name: Decimal to Octal Converter
Availability: InStock
Author: Nham Vu

Enter any decimal integer and instantly get its octal (base-8) equivalent with a step-by-step breakdown.

Decimal Input

Enter a decimal integer

Quick examples

Octal Result

Enter a number on the left to see the result.

Octal (base-8)

Decimal

Octal

Octal prefix

Step-by-step division

Step	Dividend	÷ 8	Quotient	Remainder

Reading remainders from bottom to top gives the octal result.

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Summary

Enter any decimal integer and instantly get its octal (base-8) equivalent with a step-by-step breakdown.

How it works

Type a decimal integer (positive or negative) into the input field.
The converter repeatedly divides the number by 8 and collects each remainder.
The remainders, read in reverse order, form the octal representation.
The result and a step-by-step table appear immediately below the input.
Click "Copy Result" to copy the octal value to your clipboard.

Use cases

Check octal file-permission values used in Unix/Linux chmod commands.
Verify octal literals when writing C, C++, or Python code.
Study number-base conversions for computer science coursework.
Debug embedded systems that work with octal register addresses.
Convert large integers for POSIX API constants.

Frequently Asked Questions

Related tools

Decimal To Binary Decimal To Hex Binary To Decimal

Last updated: 2026-05-23 · Reviewed by Nham Vu