Chmod Calculator
Build a Unix file permission value visually and get both the numeric (755) and symbolic (rwxr-xr-x) representations.
Owner
Group
Other
Numeric
Symbolic
rwxr-xr-x
chmod command
chmod 755 filename
Recommended Settings
Pro Tips
- •Each numeric digit is the sum of read (4), write (2), and execute (1) for that permission group - 7 means all three, 5 means read and execute only
- •The three permission groups are Owner (the file's user), Group (users in the file's group), and Other (everyone else)
- •755 (rwxr-xr-x) is the standard permission for executable scripts and directories - the owner can modify it, everyone can run or read it
- •644 (rw-r--r--) is the standard permission for regular files that shouldn't be executable, like configuration or text files
Most Popular
Most people use 755 for executable scripts and directories, or 644 for regular non-executable files
When to Use This Tool
Figure out the exact chmod value needed for a specific access pattern.
Decode what a permission value like 750 actually grants to each user group.
Get the correct numeric chmod value to hardcode into a deployment script.
Visually demonstrate how read, write, and execute bits combine into a permission value.
How It Works
Toggle read, write, and execute checkboxes independently for the owner, group, and other permission categories
Sum each category's active bits (read=4, write=2, execute=1) to compute its numeric digit
Combine the three digits into the standard three-digit chmod value, and build the matching symbolic and command-line representations
100% Private
Files never leave your device. All processing happens locally in your browser.
Lightning Fast
Powered by Client-side bitwise permission calculation for optimal performance on modern browsers.
Open Source
Built with verified, open-source libraries. Fully transparent.
Frequently Asked Questions
What do the three digits in 755 mean?
Each digit represents one permission group in order: owner, group, and other. In 755, the owner gets 7 (read+write+execute), while group and other each get 5 (read+execute).
Why is 4+2+1 the pattern for permissions?
Read, write, and execute are represented as bit flags (4, 2, 1) that can be summed independently - this lets any combination of the three be expressed as a single digit from 0 to 7.
What's the difference between 644 and 755?
644 (rw-r--r--) allows the owner to read and write but not execute, while everyone else can only read - typical for data files. 755 (rwxr-xr-x) adds execute permission for everyone, typical for scripts and directories.
Is this calculation done on a server?
No. All permission calculation happens locally in your browser using simple arithmetic.