Chmod Calculator
Convert Unix file permission checkboxes to octal and symbolic notation, and back.
| Read | Write | Execute | |
|---|---|---|---|
| Owner | |||
| Group | |||
| Others |
rwxr-xr-x
chmod 755 filename
Qu’est-ce que Chmod Calculator ?
Unix and Linux systems control file and directory access with three permission sets — owner, group, and others — each made up of read, write, and execute bits. chmod is the command used to change those permissions, and it's commonly expressed as a 3-digit octal number (like 755) or as a 10-character symbolic string (like rwxr-xr-x). This calculator converts between the two instantly: toggle the read/write/execute switches for each of owner, group, and others to see the resulting octal and symbolic notation, or type an octal value directly to see which permissions it represents — useful when you're setting file permissions on a server and want to double-check a number before running chmod.
Comment utiliser Chmod Calculator
- Toggle the Read/Write/Execute switches for Owner, Group, and Others to build the permission set you want.
- The Octal field and Symbolic notation update live as you toggle switches.
- Alternatively, type a 3-digit octal value (like 644) directly into the Octal field to set all the switches at once.
- Copy the ready-to-run chmod command at the bottom and use it on your server.
Exemples
Standard executable/script permissions
Entrée : Owner: read+write+execute, Group: read+execute, Others: read+execute
Sortie : 755 / rwxr-xr-x
Read-only for everyone
Entrée : Owner: read only, Group: read only, Others: read only
Sortie : 444 / r--r--r--
Erreurs courantes
- Confusing chmod (which controls permissions) with chown (which controls ownership) — this tool only covers the former.
- Setting 777 out of convenience during debugging and forgetting to tighten it back down afterward.
- Removing execute permission from a directory, not realizing it blocks entering the directory at all, not just running files in it.
- Assuming a 4-digit octal like 4755 is invalid — the extra leading digit sets the setuid/setgid/sticky bits and isn't covered by this calculator, which only handles the standard 3-digit owner/group/others value.
Pourquoi utiliser cet outil
- Two-way — toggle switches to get the octal, or type an octal to see the switches.
- Shows both octal and symbolic notation side by side.
- Generates a ready-to-copy chmod command.
- Runs entirely client-side; nothing is sent to a server.