Checkbox Builder
Click read/write/execute for owner, group, and others — see results update live.
Developer Tool
Chmod Calculator — Unix File Permissions Made Visual
Build Unix file permissions with checkboxes and get the numeric (755) and symbolic (rwxr-xr-x) notation instantly — including setuid, setgid & sticky bit support.
- Checkbox Builder
- Numeric + Symbolic
- Special Bits
- 100% Private
Permission Builder
| Read (4) | Write (2) | Execute (1) | |
|---|---|---|---|
| Owner | |||
| Group | |||
| Others |
Result
Numeric
755
chmod 755 filename
Features
Every Way to Read Permissions
Build visually, or type numeric or symbolic directly — everything stays in sync.
Bidirectional Sync
Type a numeric or symbolic value directly and the checkboxes update to match.
Special Bits
Full support for setuid, setgid, and the sticky bit as a fourth octal digit.
Common Presets
One click for 755, 644, 700, 777, and other frequently-used permission sets.
How It Works
Set Permissions in Seconds
- 1
Check Permissions
Toggle read, write, and execute for owner, group, and others.
- 2
Read the Result
See the numeric (e.g. 755) and symbolic (rwxr-xr-x) value instantly.
- 3
Run the Command
Copy the ready-made chmod command straight into your terminal.
FAQ
Frequently Asked Questions
chmod 755 gives the file owner full permissions (read, write, execute = 7), and gives the group and everyone else read and execute permissions only (5), but not write. It's the standard permission set for executable scripts and directories that others need to run or list but not modify.
chmod 644 gives the owner read and write access (6), and gives the group and everyone else read-only access (4). This is the standard permission set for regular files like documents, configs, and web pages that others should be able to view but not edit or execute.
Each permission has a value: read = 4, write = 2, execute = 1. Add them together for each of owner, group, and others to get one digit each (0-7). For example, read+write+execute = 4+2+1 = 7, and read+execute = 4+1 = 5.
Symbolic notation shows permissions as three groups of three characters — owner, group, others — where r=read, w=write, x=execute, and - means that permission is not granted. rwxr-xr-x means the owner has all three permissions, while group and others only have read and execute.
These are special permission bits shown as a fourth leading digit. Setuid (4) makes an executable run with the file owner's privileges. Setgid (2) makes new files in a directory inherit the directory's group. The sticky bit (1) on a directory means only the file's owner can delete or rename it, even if others have write access.
Run the command shown at the bottom of this tool in your terminal: chmod followed by the numeric value and the filename, e.g. chmod 755 script.sh. You need appropriate ownership or sudo access to change a file's permissions.
Understanding Unix File Permissions
Every file and directory on a Unix/Linux system has three permission sets — one each for the owner, the group, and others (everyone else) — and three permission types: read (r), write (w), and execute (x). Together these nine bits control exactly who can view, modify, or run a file.
Common Chmod Values
| Numeric | Symbolic | Typical use |
|---|---|---|
| 777 | rwxrwxrwx | Full access for everyone — rarely appropriate; a security risk on most servers. |
| 755 | rwxr-xr-x | Executable scripts and directories; owner can edit, everyone can run/list. |
| 750 | rwxr-x--- | Executable restricted to owner and group only. |
| 644 | rw-r--r-- | Standard file permission — owner edits, everyone else reads. |
| 664 | rw-rw-r-- | Shared files editable by owner and group, readable by others. |
| 700 | rwx------ | Private executable — only the owner can read, write, or run it. |
| 600 | rw------- | Private file — only the owner can read or write, e.g. SSH keys. |
Reading the ls -l Output
When you run ls -l, permissions appear as a 10-character string like -rwxr-xr-x. The first character indicates the file type (- for a regular file, d for a directory), followed by three groups of rwx for owner, group, and others.
Why 777 Is Usually a Bad Idea
chmod 777 grants read, write, and execute to absolutely everyone on the system — including any process or user that shouldn't have access. It's occasionally used to quickly unblock a permissions error during development, but leaving it on production files or directories is a common and serious security misconfiguration. Prefer the narrowest permission set that still lets the application function correctly.