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Chmod Calculator

Convert Unix file permissions between rwx checkboxes and octal mode in your browser - no account and no upload.

About Chmod Calculator

Convert Unix file permissions between rwx checkboxes and octal mode in your browser - no account and no upload. Toggle read, write, and execute for owner, group, and other, optionally set setuid, setgid, or sticky, then copy the octal value, symbolic string, or a ready `chmod` command. Use presets like 644 and 755 for common files and directories. Pair it with the Cron Expression Generator when you are wiring server jobs, or the Text to Binary Converter for other low-level encodings.

How to Use Chmod Calculator

  1. Pick a preset (644, 755, 777, 600, 700, 4755, 1777) or leave the default 755.
  2. Toggle Read, Write, and Execute for Owner, Group, and Other. Digits update live.
  3. Optionally enable setuid, setgid, or sticky when you need a four-digit mode.
  4. Type an octal value (3 or 4 digits, 0-7) to drive the checkboxes the other way.
  5. Set a path if you want, then copy the octal mode, symbolic string, or full chmod command. Nothing leaves this tab.

Chmod Calculator Examples

Web files 644

Owner read+write, group and other read only = 644. Typical for HTML, CSS, and config files that should not be executable.

Scripts and directories 755

Owner rwx, group and other r-x = 755. Common for directories and shell scripts so others can traverse or run without writing.

Private key 600

Owner read+write only = 600. Use for SSH private keys and secrets so group and other have no access.

Setuid binary 4755

Special digit 4 plus 755 = 4755. Symbolic mode shows s on the owner execute bit (rwsr-xr-x).

Sticky directory 1777

Special digit 1 plus 777 = 1777 (rwxrwxrwt). Classic /tmp style: anyone can write, but only the owner can delete their own files.

Common Use Cases

  • Building a chmod command before deploying on a VPS
  • Checking what 755 vs 644 means for a web root
  • Explaining setuid, setgid, and sticky bits to a teammate
  • Converting a symbolic mode from ls -l into octal
  • Setting tight modes like 600 or 700 for secrets and SSH keys

Frequently Asked Questions about Chmod Calculator

How do I convert rwx to octal?
Read is 4, write is 2, execute is 1. Add them per class (owner, group, other). rwx = 7, r-x = 5, r-- = 4. Three digits make modes like 755 or 644.
What does chmod 755 mean?
Owner can read, write, and execute (7). Group and other can read and execute (5). Often used for directories and executable scripts.
When should I use 644 vs 755?
Use 644 for normal files that should not run as programs. Use 755 for directories and scripts that need the execute bit so users can enter the folder or run the file.
What are setuid, setgid, and sticky?
They are the optional leading octal digit. Setuid (4) runs a binary as the file owner. Setgid (2) runs as the group or inherits group on new files in a directory. Sticky (1) on a directory (like /tmp) lets anyone create files but only the owner can delete them.
Why does the symbolic mode show s, S, t, or T?
When a special bit is on, the execute slot uses s/t if execute is also on, or S/T if execute is off. Example: 4644 is rwSr--r-- (setuid without owner execute).
Is anything uploaded?
No. Permission math runs only in this tab. There is no server call for the calculator.
Can I copy a full chmod command?
Yes. Set the path field (default path) and use Copy command to get something like chmod 755 path ready to paste into a shell.

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