Convert Octal to Decimal
Convert octal (base 8) to decimal instantly. Used in Unix permissions. Free online converter.
Input
Number
From Base
2-36
Results
2
Binary
Base 2
0b111111118
Octal
Base 8
0o37710
Decimal
Base 10
25516
Hexadecimal
Base 16
0xFFStep-by-Step Conversion
Step 1: Convert Decimal 255 to Binary
255 / 2 = 127 remainder 1
127 / 2 = 63 remainder 1
63 / 2 = 31 remainder 1
31 / 2 = 15 remainder 1
15 / 2 = 7 remainder 1
7 / 2 = 3 remainder 1
3 / 2 = 1 remainder 1
1 / 2 = 0 remainder 1
Result: 11111111
About This Conversion
Octal (base-8) uses digits 0-7 and is primarily encountered in Unix/Linux file permissions (chmod 755) and some older computing contexts. To convert octal to decimal, multiply each digit by 8 raised to its positional power. For example, octal 755 = (7x64) + (5x8) + (5x1) = 448 + 40 + 5 = 493. Understanding octal is essential for Linux system administrators who set file permissions daily using chmod commands.
Frequently Asked Questions
Where is octal used?
Octal is primarily used in Unix/Linux file permissions (chmod 755, chmod 644). Each octal digit represents 3 binary bits (read, write, execute).
What is octal 777 in decimal?
Octal 777 = (7x64) + (7x8) + (7x1) = 448 + 56 + 7 = 511 in decimal.