| Numeric | Symbolic | Usage |
|---|---|---|
| 755 | rwxr-xr-x | Standard directories, executables |
| 644 | rw-r--r-- | Standard files, web pages |
| 600 | rw------- | SSH keys, private files |
| 777 | rwxrwxrwx | Full access (not recommended) |
| 400 | r-------- | Read-only for owner |
Unix file permissions control who can read, write, and execute files and directories. Each file has three permission groups: owner, group, and others. Each group can have read (4), write (2), and execute (1) permissions. The numeric notation sums these values — 755 means owner has full access (7=4+2+1), while group and others can read and execute (5=4+1). The chmod command changes these permissions. Setting correct permissions is critical for server security — misconfigured permissions are one of the most common causes of security vulnerabilities in web hosting.
The Chmod Calculator is a free, browser-based network diagnostic on ipaddress.world that helps you get the job done in seconds without installing anything or creating an account. Converts between octal (755) and symbolic (rwxr-xr-x) Unix permissions. It's designed for everyday use by professionals and hobbyists alike, and it runs entirely on the page you're reading now — so your data stays on your device.
Whether you reach for it a dozen times a day or only when something breaks, Chmod Calculator is built to be fast, reliable and refreshingly simple. There are no ads inside the tool area, no sign-up walls, no usage counters and no surprise limits. You paste or drop your input, adjust a few options if needed, and get a clean result you can copy, download or share.
There are plenty of tools on the internet that claim to do the same thing. What makes Chmod Calculator different is the combination of three things: privacy, speed and focus. Privacy, because the heavy lifting happens in your browser using modern web standards — nothing gets uploaded, logged or profiled. Speed, because there's no round-trip to a remote server, so results come back as fast as your CPU can produce them. And focus, because the interface strips away everything that isn't helping you finish the task.
It's the kind of tool you bookmark once and rely on for years. No installs, no updates to babysit, no licence keys to renew — just open the page and go.
Sysadmins and developers set correct permissions on files, scripts and web directories. In practice, the audience is wide: anyone who needs a dependable, no-nonsense network diagnostic that works the first time and doesn't get in the way. Teams at startups and enterprises use it during incident response, code reviews, customer support and content production. Freelancers and students use it to avoid paying for heavyweight desktop apps they only need occasionally. Power users keep it open in a pinned tab alongside their IDE, terminal and design tools.
That's really all there is to it. Most people are in and out within a minute, and the workflow becomes muscle memory after the first couple of uses.
Privacy is not an afterthought on ipaddress.world. Chmod Calculator is built so that whatever you paste, drop or type stays with you. There is no upload step for the data you're working with, no server-side storage, no analytics inside the tool panel that would watch what you do. When you close the tab, everything is gone. This matters when you're handling code, configuration, tokens, internal documents, client assets or personal files — exactly the things you should never be pasting into random online tools.
Bookmark this page so you can get back to it instantly. If you use Chmod Calculator often, keep it open in a pinned browser tab — it loads in a fraction of a second and stays ready. Try the keyboard: most actions have sensible defaults so you can press Enter instead of clicking. And don't forget to scroll down to the Related Tools section below — ipaddress.world has dozens of tools that complement each other, and chaining two or three together often solves problems that would otherwise need a custom script.
Where does the data come from?
The tool queries public DNS, WHOIS, certificate authorities and other trusted public sources.
Is it accurate?
Results reflect what public infrastructure reports in real time. Propagation and caching can affect freshness.
Do I need to sign in?
No. All checks are available anonymously.
Are there rate limits?
Fair use is unlimited. Automated bulk use may be throttled to protect the service.
If you spot something that could be better, or you'd like to see a feature added to Chmod Calculator, we'd love to hear about it. ipaddress.world is maintained as a long-term project, and feedback from real users is what shapes each tool over time. Thanks for using it — and happy building.