Numbers / base 10 → base 8
Convert Decimal to Octal
Convert signed integers between binary, octal, decimal, and hexadecimal. Convert Decimal (base 10) to Octal (base 8). Find the formula, worked examples, unit definitions, and practical guidance below.
How to convert decimal to octal
Arbitrary-precision integers preserve all digits within the 4096-character input limit. Fractions, exponent notation, prefixes such as 0x, and two’s-complement bit patterns are not accepted. Negative integers keep a minus sign.
Worked examples
Read each digit as a coefficient of a power of 10, then express the integer using powers of 8. Repeated division by 8 yields the target digits from right to left.
- 42 (base 10) = 52 (base 8)
- 255 (base 10) = 377 (base 8)
About Decimal
Decimal uses base 10. Its place values are powers of 10; the same integer is represented by a different sequence of digits in another base.
About Octal
Octal uses base 8. Its place values are powers of 8; the same integer is represented by a different sequence of digits in another base.
Definitions and sources
For a different quantity or formatting task, see the related other conversion tools.
Browse every numbers conversion →