Decimal to Octal Calculator
Convert a base-10 decimal number to base-8 octal notation.
About the Decimal to Octal Calculator
Decimal (base-10) is the everyday number system using digits 0-9, while octal (base-8) uses only digits 0-7. Octal was historically popular in early computing as a compact way to represent binary values, since each octal digit maps to exactly three binary digits.
Formula: Repeatedly divide the decimal number by 8 and record the remainders, then read them in reverse order to get the octal digits.
For example, decimal 15 converts to octal 17 (one group of eight plus a remainder of seven: 1×8 + 7 = 15). Decimal 64 converts to octal 100, since 64 is exactly 82.
Useful for computer science coursework, interpreting legacy Unix file permission codes (like chmod 755) and low-level programming where octal notation is still occasionally used.