What does 755 mean in chmod?

755 means owner has read, write, and execute (7); group has read and execute (5); others have read and execute (5). The symbolic equivalent is rwxr-xr-x.

What permissions should a web file have?

Typically 644 (rw-r--r--) for files and 755 (rwxr-xr-x) for directories. Executable scripts may need 755. Avoid 777, it grants write access to everyone.

Is my data sent to a server?

No. All permission calculations are pure JavaScript running in your browser.

What is the difference between the numeric and symbolic format?

The numeric (octal) format uses digits 0 to 7. The symbolic format uses letters (r, w, x) and dashes. Both describe the same permissions, use whichever is required by your system or documentation.

Chmod calculator

Chmod calculator is a developer tool that converts Unix file permissions between visual checkboxes, octal numbers, and symbolic notation. It updates all three views as you tick read, write, or execute bits for owner, group, and other, and accepts direct numeric input like 755. The tool runs in your browser.

Dedicated pages

Direct links for file permission topics.

Unix file permissions calculator

Calculate Unix file permissions by clicking read, write and execute bits. See the numeric (755) and symbolic (rwxr-xr-x) notation instantly. Free, in-browser.

Chmod permissions calculator

Convert chmod numeric values to symbolic notation and vice versa. Click permission bits or type the octal value. Free, in-browser.

Linux file permissions

Understand and calculate Linux file permissions. Click to set read, write and execute bits for owner, group and other. Shows numeric and symbolic output. Free, in-browser.

How to calculate chmod permissions

Tick the read, write, and execute checkboxes for Owner, Group, and Other.
The numeric (octal) and symbolic permission strings update instantly.
Or type an octal value like 755 directly into the number input to set the checkboxes.
Copy the numeric or symbolic value to use in a chmod command.

Common uses

Setting the correct file permissions for web server files and directories alongside subnet planning with the CIDR calculator
Understanding what a chmod value like 644 or 755 actually means, or use the number base converter to translate octal permission bits into binary
Generating chmod commands for scripts, deployment procedures, or documentation

Technical specification

Algorithm or formula: Bitwise mapping of three rwx triplets (read=4, write=2, execute=1) per principal (owner, group, other). The octal value is the concatenation of the three sums (e.g. rwx r-x r-x = 755).
Browser API or library: Pure JavaScript bitwise operations. No external library.
Input limits: Accepts three-digit octal values (000 to 777) or any combination of nine rwx checkboxes.
Output: Octal number, symbolic string (rwxr-xr-x), and a ready-to-paste chmod command.
Known limitations: Special bits (setuid, setgid, sticky) are not exposed in this simplified UI. ACLs and SELinux contexts are out of scope.

Frequently asked questions

What does 755 mean in chmod?: 755 means owner has read, write, and execute (7); group has read and execute (5); others have read and execute (5). The symbolic equivalent is rwxr-xr-x.
What permissions should a web file have?: Typically 644 (rw-r--r--) for files and 755 (rwxr-xr-x) for directories. Executable scripts may need 755. Avoid 777, it grants write access to everyone.
Is my data sent to a server?: No. All permission calculations are pure JavaScript running in your browser.
What is the difference between the numeric and symbolic format?: The numeric (octal) format uses digits 0 to 7. The symbolic format uses letters (r, w, x) and dashes. Both describe the same permissions, use whichever is required by your system or documentation.

Reviewed and tested May 26, 2026.

	Read	Write	Execute	Value
Owner				7 (rwx)
Group				5 (r-x)
Other				5 (r-x)