Loading tool…
Calculate Unix file permissions.
Paste or type your input here, Chmod Calculator is loading…
One task, zero friction: calculate unix file permissions. Chmod Calculator runs right in your browser as part of ToolsMonk's developer tools lineup: no installs, no account, and nothing to configure before you start.
Typical jobs it handles include working out the chmod number for a set of permissions, decoding what a permission like 644 or 755 actually means, and setting correct permissions for web files and scripts. The same page works on desktop, tablet, and mobile, so it is equally quick for a single urgent task and for work you repeat every week.
The design goal is simple: practical output on the first try, with a privacy-friendly workflow and the rest of the ToolsMonk library one click away.
| Price | Free, no signup, no paywall, no watermark |
|---|---|
| Works on | Any modern browser: desktop, tablet, and mobile |
| Processing | In your browser, files never leave your device |
| Account required | None |
| Category | Developer Tools |
Toggle read, write, and execute for owner, group, and others
The octal number (e.g. 755) and symbolic notation (rwxr-xr-x) update live
Or enter an octal number to see what it permits
Copy the chmod value for your command
Converts Unix file permissions between symbolic (rwx) and octal (e.g. 755)
Toggle read/write/execute for owner, group, and others
Shows the matching chmod number and symbolic notation
Explains what each permission set allows
Runs in your browser, nothing is uploaded
Free, with no signup and no rate limit
Working out the chmod number for a set of permissions
Decoding what a permission like 644 or 755 actually means
Setting correct permissions for web files and scripts
Learning Unix/Linux file permissions
At its core, Chmod Calculator does one thing well, calculate unix file permissions, with instant, accurate results. There is no software to install and no account to create; the tool is ready the moment the page loads.
Privacy and portability drive the design: all processing runs locally in your browser, so your files and data never leave your device. It behaves identically in every modern browser, from a desktop workstation to a phone.
Chmod Calculator converts Unix/Linux file permissions between the symbolic form (rwxr-xr-x) and the octal number used with chmod (like 755), with checkboxes for read, write, and execute across owner, group, and others.
The octal system clicks once you see the arithmetic: each of the three digits covers one group, owner, group, others, and is the sum of read (4), write (2), and execute (1). So 7 is all permissions, 5 is read+execute, 6 is read+write, and a number like 755 reads as 'owner everything, group and others read+execute'. The calculator shows both notations live so you can learn by toggling.
Two everyday values dominate: 644 (rw-r--r--) for regular files, where the owner edits and others read, and 755 (rwxr-xr-x) for directories and executables. A subtlety worth knowing is that 'execute' on a directory means the right to enter and traverse it, which is why folders need 755, not 644.
A security note the tool encourages: avoid 777 (full access for everyone) on servers, as it lets anyone modify the file and is rarely truly needed, set the minimum permissions instead. Everything runs in your browser with nothing uploaded. Pair it with the other ToolsMonk developer tools for your sysadmin and web tasks.
Rule of thumb: 644 for files, 755 for directories and scripts
Avoid 777 on web servers, it's a security risk and rarely necessary
Each digit = read(4) + write(2) + execute(1) for owner / group / others
Common questions about this tool, its workflow, and what to expect before you use it.
No ratings yet. Be the first to say how Chmod Calculator worked for you.
Reviews appear here once our team has read them, so everything you see is from someone who signed in and used the tool.
Get notified about new tools, features, and tips. No spam, unsubscribe anytime.
Remove whitespace from JSON for smaller payload size.
Try itBeautify and format SQL queries.
Try itFormat and beautify XML documents.
Try itEncode and decode HTML entities.
Try itParse and analyze HTTP response headers.
Try itBuild, describe in plain English and preview the next run times of cron schedules.
Try itCreate JWT tokens for testing and development.
Try itSend HTTP requests and inspect responses.
Try itWriting a roundup or tutorial? Embed the live Chmod Calculator so readers use it right on your page, or drop in a ready-made card that links to it. Free to use, always.
Preview
Calculate Unix file permissions.
Use Chmod Calculator free →Live tool (iframe)
Readers use the real, working tool right on your page, with a small credit line underneath.
Embed card (HTML)