File Permission Calculator
Convert Linux file permissions between octal, symbolic and chmod notation instantly.
About File Permission Calculator
Linux file permissions can be expressed as a 9-character symbolic string (owner, group, others — each a read/write/execute triplet) or as a 3-digit octal number. Each octal digit sums read (4), write (2) and execute (1) for that class. This calculator parses either format and converts to the other, plus a breakdown by owner, group and others. A fourth leading octal digit represents the setuid/setgid/sticky bits.
Formula
Octal digit from permissions
digit = 4×read + 2×write + 1×execute
- r
- 1 if read is set, else 0
- w
- 1 if write is set, else 0
- x
- 1 if execute is set, else 0
Worked example
With the default values below, File Permission Calculator returns Octal Mode of 754. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Permission Mode
- rwxr-xr--
Results
- Octal Mode
- 754
- Symbolic Mode
- rwxr-xr--
- Owner
- rwx (read + write + execute)
- Group
- r-x (read + execute)
- Others
- r-- (read)
Step by step
- 1Values used
- 2Octal digit from permissions
- 3Octal Mode= 754
- 4Symbolic Mode= rwxr-xr--
- 5Owner= rwx (read + write + execute)
- 6Group= r-x (read + execute)
- 7Others= r-- (read)
Assumptions and limits
- The result is derived only from the single input 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.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
What does chmod 754 mean?
754 breaks down as owner=7 (rwx, full access), group=5 (r-x, read and execute), others=4 (r--, read only). In symbolic form that is rwxr-xr--.
What is the difference between symbolic and octal notation?
Symbolic notation spells out permissions as letters (r, w, x) for owner, group and others in a 9-character string. Octal notation compresses each triplet into a single digit 0-7 by summing 4 (read) + 2 (write) + 1 (execute).
What do the T and t characters mean in permissions?
A lowercase t in the execute position of 'others' means the sticky bit is set and execute is also set. An uppercase T means the sticky bit is set but execute is not. The sticky bit on a directory restricts file deletion to the file's owner.
Can I enter a 4-digit octal mode?
Yes. A 4-digit mode's leading digit encodes setuid (4), setgid (2) and sticky (1) special bits; the remaining three digits are the normal owner/group/others permissions.