Why it matters
File permissions decide who can read your config, run your scripts and write to your uploads folder. A careless 777 on a web server lets any process change your site, and a 600 on a public folder breaks it.
This calculator keeps the octal, symbolic and checkbox views in step, applies changes the way chmod does (including the capital X rule for folders), shows what a umask means for new files, and warns when a mode is risky.
How it works
- InputTicks, an octal mode or ls -l output
- In your browserConverted between octal and symbols
- OutputThe mode, the command and warnings
Where it fits in a designer's workflow
- Plan
- Design
- Build
- Test
- Launch
By the numbers
644 -rw-r--r--644 file600 -rw-------600 secret755 drwxr-xr-x755 dir750 drwxr-x---750 dir1777 drwxrwxrwt1777 /tmp2775 drwxrwsr-x2775 shared4755 -rwsr-xr-x4755 setuid
Show the numbers as a table
| Mode | Octal | Symbolic |
|---|---|---|
| 644 file | 644 | -rw-r--r-- |
| 600 secret | 600 | -rw------- |
| 755 dir | 755 | drwxr-xr-x |
| 750 dir | 750 | drwxr-x--- |
| 1777 /tmp | 1777 | drwxrwxrwt |
| 2775 shared | 2775 | drwxrwsr-x |
| 4755 setuid | 4755 | -rwsr-xr-x |
How to use it
- Tick the permissions, or type an octal or symbolic mode.
- Add special bits if you need them.
- Try a symbolic change to see the result.
- Copy the chmod command.
FAQ
What do 755 and 644 mean?
755: the owner can read, write and run; everyone else can read and run. 644: the owner can read and write; everyone else can only read. They're the usual modes for folders and files.
What does capital X do?
It adds execute only to folders, or to files that already have execute for someone. That's why chmod -R a+rX is safe for web roots.
Why is 777 dangerous?
Anyone on the system can change or replace the file. On a shared or compromised server, that's a way in.
What's a umask?
The permissions removed from new files and folders. With umask 022, new files get 644 and folders 755.
