chmod Calculator — Linux File Permission Generator
Our free chmod calculator makes Linux file permissions easy to understand and configure. Use the interactive checkbox grid to set read, write, and execute permissions for owner, group, and others. The numeric (octal) and symbolic notations update in real-time, along with the ready-to-use chmod command.
You can also enter a numeric code like 755 and see the permissions visually. Common presets for web servers (644 for files, 755 for directories) are available with one click.
Two rules explain almost every permission problem. Directories need the execute bit to be entered at all, which is why 644 on a folder produces a permission denied error that looks nothing like a permissions issue, and why 755 is the usual answer. And 777 is almost never the right fix — it makes a file writable by every account on the machine, and on a shared host that includes other people's sites. When something will not run, the answer is usually a missing execute bit on the file or a missing one on a parent directory.
Common chmod values
| Command | Symbolic | Typical use |
|---|---|---|
chmod 644 | rw-r--r-- | Regular files such as HTML, images, and config files |
chmod 755 | rwxr-xr-x | Directories, scripts, and programs everyone may run |
chmod 600 | rw------- | Private files such as SSH private keys and .env files |
chmod 700 | rwx------ | Private directories such as ~/.ssh |
chmod 775 | rwxrwxr-x | Shared project folders a group edits together |
chmod 400 | r-------- | Read-only secrets, such as an AWS .pem key |
Symbolic mode changes one bit without touching the rest: chmod +x deploy.sh makes a script executable, and chmod g+w shared/ lets the group write. chmod -R 755 applies a value to a folder and everything in it, but it also makes every file executable, so prefer find . -type d -exec chmod 755 {} + for folders and find . -type f -exec chmod 644 {} + for files. Running the script on a schedule? Build the timing with the cron expression generator.
How to use chmod Calculator
- Check the boxes for Read, Write, and Execute for Owner, Group, and Others.
- Watch the numeric and symbolic notations update in real time.
- Alternatively, enter a numeric code (e.g., 755) to see its visual representation.
- Copy the generated chmod command to apply it.
Features
- Interactive permission matrix — Owner/Group/Others × Read/Write/Execute checkboxes.
- Real-time numeric (octal) and symbolic notation — Updates instantly as you toggle.
- Ready-to-copy chmod command — Get the exact command immediately.
- Reverse lookup — Enter a numeric code to see permissions visually.
- Common presets — 644, 755, 777, 600, 400 with one click.
- Permission explanation in plain English — Understand what each setting means.
Frequently Asked Questions
What does chmod 755 mean?
chmod 755 sets these permissions: Owner can read, write, and execute (7=rwx). Group can read and execute (5=r-x). Others can read and execute (5=r-x). This is the standard permission for directories and executable scripts on web servers.
What is the difference between 644 and 755?
644 (rw-r--r--) allows the owner to read and write, while group and others can only read. 755 (rwxr-xr-x) adds execute permission for all. Use 644 for regular files and 755 for directories and scripts.
How do I read symbolic permissions like rwxr-xr-x?
The 9 characters are split into 3 groups of 3: owner (rwx), group (r-x), others (r-x). 'r' = read, 'w' = write, 'x' = execute, '-' = no permission. Our calculator shows both notations side by side.
Why does 777 keep getting recommended, and why should I avoid it?
Because it makes the error go away. It also makes the file writable by every user and every process on the machine, which on shared hosting includes other customers. Almost every case where 777 works is fixed properly by 755 on directories, 644 on files, and correcting the owner with chown.
Why can I not open a folder even though I have read permission?
Because directories use the execute bit to mean traversal, not execution. Read lets you list the names inside; execute lets you enter and reach what is in it. A directory at 644 will list but not open, which is why directories are 755 where files are 644.