Linux Permissions Calculator (chmod)
Convert between permissions such as 750 and rwxr-x---, or use the checkboxes to build a mode. All calculations run locally in your browser; nothing you enter is uploaded.
This calculator covers the ordinary owner, group and others permission bits. It explains a mode; it does not decide which permissions your application needs.
Enter exactly three digits from 0 to 7, or nine permission characters such as rwxr-x---. Leave out the leading file-type character shown by ls -l.
| User class | Read (4) | Write (2) | Execute / search (1) |
|---|---|---|---|
| Owner | |||
| Group | |||
| Others |
Selected mode: 750 = rwxr-x---
Replace the placeholder with your own path. This command changes one file or directory; it does not change ownership or apply recursively.
How the numbers work
Each digit adds read (4), write (2) and execute/search (1) for one class: owner, group, then others. For example, 750 means:
- Owner: 7 — read, write and execute/search.
- Group: 5 — read and execute/search.
- Others: 0 — no permissions granted by these bits.
The notation is rwxr-x---. In ls -l, an additional character appears before it to identify the file type, such as - for a regular file or d for a directory. That character is not part of the nine permission bits entered here.
For a file, read means reading its contents, write means changing its contents, and execute permits running it as a program. Execute permission alone does not make arbitrary content a runnable program.
For a directory, read allows listing entry names, write controls changes to directory entries, and execute (search) allows traversal and access to entries by name. Creating, deleting or renaming entries generally requires both write and search on the containing directory. Accessing a file also depends on search permission on directories along its path. Deleting a file is governed by its containing directory, rather than the file's write bit alone.
What this calculator does not check
These are the ordinary Unix permission bits, not a complete access diagnosis. Owner permissions apply to the owner; group permissions apply to a non-owner matching the file's group; others apply to users in neither class. The classes are not added together.
The calculator does not inspect ownership, user/group IDs, ACLs, special bits (setuid, setgid or sticky), read-only mounts, NFS export rules or other security controls. A three-digit chmod command is not a guarantee of removing existing special bits; GNU chmod can preserve setuid and setgid on directories.
For Docker bind mounts, the identity used by the container process and the host path's ownership matter too. For Synology NFS shares, server-side permissions and identity mapping may also affect access. Changing a permission number alone will not resolve every access problem, and 777 is not a general troubleshooting fix.
Related guides:
Reference: GNU Coreutils: Numeric Modes and Directory Setuid and Setgid Bits.