Numbers / base 8 → base 10
Convert Octal to Decimal
Convert signed integers between binary, octal, decimal, and hexadecimal. Convert Octal (base 8) to Decimal (base 10). Find the formula, worked examples, unit definitions, and practical guidance below.
How to convert octal to decimal
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 8, then express the integer using powers of 10. Repeated division by 10 yields the target digits from right to left.
- 52 (base 8) = 42 (base 10)
- 377 (base 8) = 255 (base 10)
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.
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.
Definitions and sources
For a different quantity or formatting task, see the related other conversion tools.
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