What does this tool do?
The Chmod Calculator lets you set Linux and Unix file permissions with visual checkboxes and instantly get the octal code (e.g. 755), symbolic notation (e.g. -rwxr-xr-x), and a ready-to-run chmod command. It is handy for sysadmins, developers, and anyone configuring a server.
How to use it
- Enter your configuration details.
- Review the generated output.
- Copy the ready-to-use code or file.
How permissions work
Every file has three permission groups: owner (u), group (g), and others (o). Each group has read (r=4), write (w=2), and execute (x=1). Adding the values you grant produces a digit from 0 to 7 per group, and the three digits together form the octal code. For example, owner 4+2+1=7 plus group and others 4+0+1=5 each gives 755. As you tick the checkboxes, the octal, symbolic, and command update instantly.
Common use cases
644 is typical for documents and web content: the owner reads and writes while others only read. 755 suits scripts and directories because execute/enter access is needed. 600 protects secrets like SSH private keys that only the owner should touch, and 700 fits fully private folders. Click a preset to apply the value in a second, then copy the chmod command and paste it straight into your terminal.
Frequently asked questions
What is the difference between 755 and 644?
755 keeps the execute (x) bit on, which directories and scripts need. 644 has no execute bit, making it ideal for plain content files such as text, HTML, and images.
What does the leading dash in the symbolic output mean?
The first character in -rwxr-xr-x indicates the file type. A dash (-) marks a regular file and d marks a directory. This tool assumes a regular file, so it starts with a dash.
Can I type the octal value directly?
Yes. Enter a valid three-digit value such as 600 or 755 and the checkboxes, symbolic notation, and command all update automatically.
Is Chmod Calculator free?
Yes. Chmod Calculator and all 300+ tools on MagmaNex are completely free with no signup or account required.
Is my data safe?
Yes. Everything runs locally in your browser. The data you enter is never sent to a server, stored, or shared.
Does it work on mobile?
Yes. Chmod Calculator works on phones, tablets and desktops — no app download needed.
🔒 Privacy: everything runs in your browser, your data is never sent to a server.