Octal Permission Calculator
Convert numeric octal permission codes like 755 or 644 into readable rwx notation.
About Octal Permission Calculator
Each octal permission digit is the sum of read (4), write (2) and execute (1) for that class of user. Toggling the checkboxes for owner, group and others rebuilds each digit from the checked bits, producing both the 3-digit octal code and the equivalent symbolic string, plus a ready-to-run chmod command.
Formula
Octal digit from bits
digit = 4×read + 2×write + 1×execute
- r
- 1 if read checked
- w
- 1 if write checked
- x
- 1 if execute checked
Worked example
With the default values below, Octal Permission Calculator returns Octal Code of 754. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Owner Read
- Yes
- Owner Write
- Yes
- Owner Execute
- Yes
- Group Read
- Yes
- Group Write
- No
- Group Execute
- Yes
- Others Read
- Yes
- Others Write
- No
- Others Execute
- No
Results
- Octal Code
- 754
- Symbolic Mode
- rwxr-xr--
- chmod Command
- chmod 754 filename
- Owner Digit
- 7
- Group Digit
- 5
- Others Digit
- 4
Step by step
- 1Values used
- 2Octal digit from bits
- 3Octal Code= 754
- 4Symbolic Mode= rwxr-xr--
- 5chmod Command= chmod 754 filename
- 6Owner Digit= 7
- 7Group Digit= 5
- 8Others Digit= 4
Assumptions and limits
- The result is derived only from the 9 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
- Figures are rounded for display to whole numbers, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
Why is read worth 4, write worth 2 and execute worth 1?
These are powers of two (2^2, 2^1, 2^0), so any combination of the three permissions maps to a unique digit from 0 to 7, exactly matching a 3-bit binary value.
What is the most common octal code for scripts?
755 (rwxr-xr-x) is common for executable scripts and directories: the owner gets full control while group and others can read and execute but not modify.
What is the most common octal code for regular files?
644 (rw-r--r--) is typical for regular files: the owner can read and write, while group and others can only read.