chmod Permissions Calculator
An interactive calculator to figure out Linux file permissions. Convert between numeric (755), symbolic (rwxr-xr-x), and checkboxes.
| Read (r) | Write (w) | Execute (x) | |
|---|---|---|---|
| Owner (u) | |||
| Group (g) | |||
| Others (o) |
You can type directly into both fields. You can also paste the result of ls -l (e.g. -rwxr-xr-x).
| Target | Symbol | Octal | Allowed actions |
|---|
| Numeric | Symbolic | When to use |
|---|---|---|
| 644 | rw-r--r-- | Default for regular files โ e.g., HTML, images, config files. Everyone can read, only owner can modify. |
| 755 | rwxr-xr-x | Default for directories/executable scripts โ Only owner can modify, others can read and execute. |
| 600 | rw------- | Sensitive information โ .env, API keys, personal configs. Only owner can read and write. |
| 700 | rwx------ | Owner-only directory โ e.g., ~/.ssh. |
| 400 | r-------- | Read-only key file โ e.g., SSH private key (id_rsa). |
| 664 | rw-rw-r-- | Files edited by multiple users in the same group. |
| 775 | rwxrwxr-x | Directory shared by users in the same group. |
| 1777 | rwxrwxrwt | Public temporary directory (/tmp) โ Everyone can write, but cannot delete others' files. |
| 777 | rwxrwxrwx | Everyone can do everything โ NOT recommended. Do not use even as a temporary workaround for permission issues. |
| Permission | Value | Description |
|---|---|---|
| r (read) | 4 | Read file contents / List directory contents |
| w (write) | 2 | Modify file contents / Create and delete files in directory |
| x (execute) | 1 | Execute file / Enter directory (cd) |
| Sum | 7 = 4+2+1 | The sum is used for each position (owner, group, others) โ 755 = rwx(7), r-x(5), r-x(5) |
| setuid | 4000 | Run with the file owner's permissions |
| setgid | 2000 | Run with the group's permissions / For directories, new files inherit the group |
| sticky | 1000 | In a directory, only the owner can delete their own files |
What is the chmod Permissions Calculator?
Tired of guessing what `chmod 755` means? This chmod permissions calculator makes managing file permissions on Linux or macOS foolproof. Check boxes for owner, group, and other permissions to see the numeric (octal) and symbolic (`rwxr-xr-x`) notations update instantly. You can also type a value in either format to see the corresponding permissions. It even generates the complete `chmod` command, ready to copy and paste into your terminal, with an option for recursive changes. Live explanations and warnings help you avoid common mistakes like using `777`.
How to use
- Select the Read (r), Write (w), and Execute (x) permissions for each of the `Owner (u)`, `Group (g)`, and `Others (o)` targets.
- The `Numeric (octal) notation` and `Symbolic notation` fields update in real time. You can also type directly into either field to set the permissions.
- Click a preset from the `Common permissions` list, such as `755` or `644`, to apply it instantly.
- Enter a `Target file/path` and check `Apply recursively (-R)` if needed. The complete `chmod` commands will be generated for you to copy.
- Check the `Permission meaning` table and any warnings to understand the effects of your selection and prevent security issues.
Frequently asked questions
What does chmod 755 mean?
It gives the owner read, write, and execute (4+2+1=7), and the group and others read and execute (4+1=5). This is common for directories and executable files.
What's the difference between permissions 644 and 755?
The main difference is execute (x) permission. 644 (rw-r--r--) is for files that shouldn't be executed, like images. 755 (rwxr-xr-x) is for scripts or directories.
Why is 777 permission dangerous?
It allows everyone to read, write, and execute the file. On a web server, this is a major security risk, as anyone could upload and run malicious code.
What are setuid, setgid, and the sticky bit?
These are special permissions. `setuid` lets a file run with the owner's privileges, `setgid` with the group's. A `sticky` bit on a directory lets users delete only their own files.