Decimal to Octal (Base 10 to Base 8

Octal (Base 8) uses 8 distinct digits (0 to 7). It is used in computing and Unix file permissions (e.g. chmod 755) where each octal digit corresponds to 3 binary bits.

To use the Decimal to Octal (Base 10 to Base 8) Converter, enter your Decimal Integer (Base 10). The calculator instantly computes Octal (Base 8), Hexadecimal Equivalent (Base 16) and more. Results update in real time as you change any input — no submit button needed.

How to Use This Calculator

Enter your Decimal Integer (Base 10) (e.g. 100 in dec). Results update instantly as you type — adjust any value to compare scenarios.

The Formula

Repeatedly divide decimal integer by 8 and record remainder digits (0-7):

Decimal 100 = 1 × 8² + 4 × 8¹ + 4 × 8⁰ = Octal 144

Worked Example

Convert Decimal 100:

Octal = 144 (Base 8) | Hexadecimal = 0x64 | Binary =

1100100.

Understanding Your Result

Unit conversion precision: round to the same number of significant figures as your original measurement. Converting 6 feet to meters gives 1.8288 m — but if your measurement was approximate (±1 inch), expressing more than 2 decimal places is false precision. For international trade and technical specifications, SI units (meters, kilograms, liters) are the standard. US customary units (feet, pounds, gallons) differ from Imperial UK units: 1 US gallon = 3.785 L vs. 1 UK gallon = 4.546 L.