Chmod calculator
Tick the rwx permissions: octal and symbolic notation live.
- Instant
- Free
- Private (processed locally)
- No sign-up
Linux permissions, without the mental arithmetic
On Linux and macOS, every file carries nine rights: read, write, execute, for three audiences (owner, group, others). This tool presents them as checkboxes and shows live the octal code, the rwx notation and the ready-to-copy chmod command.
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Tick the rights
Or type the octal code directly (e.g. 644).
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Read the notations
Octal, symbolic rwxr-xr-x and the full command.
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Use a preset
The most common codes in one click.
The chmod codes to know
| Octal | Symbolic | Typical use |
|---|---|---|
| 644 | rw-r--r-- | Files (HTML, images, configs) |
| 755 | rwxr-xr-x | Folders, scripts, executables |
| 600 | rw------- | Private files (SSH keys) |
| 700 | rwx------ | Private personal folders |
| 777 | rwxrwxrwx | Avoid (everyone, everything) |
Golden security rule: grant the minimum rights needed. 644 for files, 755 for folders and executables cover almost every need; reserve 600/700 for sensitive content.
Frequently asked questions
How do I read an octal code like 755?
Each digit covers a group (owner, group, others) and adds up the rights: read = 4, write = 2, execute = 1. 7 = 4+2+1 (rwx), 5 = 4+1 (r-x). So 755 = rwxr-xr-x: full rights for the owner, read + execute for others.
What’s the difference between 644 and 755?
644 (rw-r--r--) suits data files: the owner reads and writes, others only read. 755 (rwxr-xr-x) adds the execute right, essential for programs, scripts and… directories, which must be “traversable”.
Why does a folder need the execute right?
On a folder, the “x” right doesn’t mean execute but “enter”: without it, you can’t access the files inside, even knowing their names. Hence the default 755 on directories, versus 644 for files.
Should I avoid 777?
Yes, almost always. 777 (rwxrwxrwx) gives everyone all rights, including write access for any user — a classic security hole. Always aim for the minimum needed: 644 or 755 cover the vast majority of cases.