Convert Decimal to Octal
Convert decimal to octal (base 8) instantly. Used for Unix file 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
Converting decimal to octal is done by repeatedly dividing by 8 and recording remainders. This is useful when working with Unix file permissions, where octal notation is the standard (e.g., 755, 644, 600). Each octal digit represents 3 binary bits, making it a compact way to express groups of 3-bit permission flags (read=4, write=2, execute=1). Understanding decimal-to-octal conversion helps system administrators quickly calculate and verify chmod permission values.
Frequently Asked Questions
How do I convert decimal to octal?
Divide the decimal number repeatedly by 8 and record remainders. Read remainders in reverse order for the octal result.
What is decimal 493 in octal?
Decimal 493 in octal is 755. This is the standard permission for executable files and directories in Unix.