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Chmod Calculator

Convert Unix file permissions between numeric, symbolic, and ls-style formats.

Numeric:

User (u)

Group (g)

Other (o)

Result
chmod 0755-rwxr-xr-xchmod u+rwx,g+rx,o+rx

4000 setuid · 2000 setgid · 1000 sticky bit — shown as s/S, s/S, t/T when combined with execute (lowercase if execute is set, uppercase if not).

Numeric mode: r=4, w=2, x=1, summed per class. 0 = 0-special + 755 perms.

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Convert Unix file permissions between numeric (755), symbolic (u=rwx,g=rx,o=rx), and ls-style (-rwxr-xr-x) formats. Toggle read/write/execute per class, handle setuid/setgid/sticky bits, and copy ready-to-run chmod commands.

[x]Features
  • -Numeric, symbolic, and ls-style output at once
  • -Checkbox controls for user/group/other permissions
  • -Special bits: setuid (4000), setgid (2000), sticky (1000)
  • -Common presets (644, 755, 600, 700, and more)
  • -Copy ready-to-run chmod commands
>Use Cases
  • >Setting file permissions on a server
  • >Explaining ls -l permission strings to a team
  • >Migrating configs between systems
  • >Learning how numeric modes map to rwx

Frequently Asked Questions

>What is the difference between 755 and 644??
755 = owner can read/write/execute, group and others can read/execute (common for directories and scripts). 644 = owner can read/write, group and others can only read (common for files).
>What are setuid, setgid, and the sticky bit??
Special bits that change behavior: setuid runs a binary with the owner's privileges, setgid inherits group ownership on directories, and the sticky bit (e.g. /tmp) prevents others from deleting your files.
>Is 777 safe??
Generally not — it lets anyone read, modify, and execute the file. Prefer minimal permissions and add them only where needed.