Decimal to Octal Converter

Convert a decimal (base 10) number to octal (base 8). Octal groups bits three at a time and still shows up in Unix file permissions. Type a decimal number to see octal, binary, and hex.

Worked example

64 (decimal) → 100 (octal)

64 = 1 × 8² + 0 × 8 + 0, so 64 is 100 in octal.

Decimal (Base 10)

Binary (Base 2)

Octal (Base 8)

Hexadecimal (Base 16)

Conversion details will appear here

Frequently asked questions

Where is octal still used?

Most commonly in Unix file permissions (for example chmod 755), where each octal digit encodes read/write/execute bits.