Chmod Calculator
Calculate Unix file permissions in octal and symbolic notation
About Chmod Calculator
Tick read, write and execute for owner, group and others to get the octal mode, the symbolic string such as rwxr-xr-x and the corresponding chmod command. It also works in reverse: type a three-digit mode like 750 and apply it to update the checkboxes. Handy when writing deploy scripts, locking down SSH keys or fixing web server permissions.
Category: Text.
Frequently asked questions
What do the three chmod digit groups represent?
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The three digits represent permissions for owner, group, and others respectively. Each digit is the sum of read (4), write (2), and execute (1). 755 means owner has full access (7=4+2+1) and group/others can read and execute (5=4+1).
What does the execute bit mean for a directory?
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For directories, the execute bit means 'traverse' — the ability to enter the directory and access files inside it. Without it, a user cannot cd into the directory even if they have read permission.
What is the difference between chmod 644 and 755?
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644 is typical for files (owner can read/write, others can only read — not execute). 755 is typical for directories and executables (owner has full access, others can read and execute/traverse).
Does it support setuid, setgid or the sticky bit?
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No. The calculator covers the standard three-digit modes for owner, group and others, and the octal field accepts exactly three digits from 0 to 7, so four-digit modes such as 4755 or 1777 can't be entered. Symbolic notation is shown as output only.