Compare chmod numeric values and rwx in the browser
Select Owner, Group, Other, and special Bits, then check octal notation, rwx, and numeric chmod commands entirely in the browser.
Convert rwx to numeric chmod notationConclusion: rwxr-xr-x is 755, and rw-r--r-- is 644
Calculate Owner, Group, and Other independently in groups of three characters.
The leading - in -rwxr-xr-x and the leading d in drwxr-xr-x indicate the entry type; they are not digits of 755.
Before expanding permissions, check who needs which operation on which Path.
Add 4, 2, and 1 for every three characters.
rwx is 4+2+1=7, r-x is 4+0+1=5, and r-- is 4. Add missing Permissions as 0.
The current tool accepts - and d as prefixes in 10-character notation. It does not automatically parse file types such as l or c, so enter the nine permission characters.
| Account to check | Confirmation details | judgment |
|---|---|---|
| rwx | 4+2+1 | 7 |
| rw- | 4+2+0 | 6 |
| r-x | 4+0+1 | 5 |
| r-- | 4+0+0 | 4 |
How to verify results with the chmod permission calculator
- Enter rwxr-xr-x in the symbolic format field.
- Check the Owner, Group, and Other Checkboxes.
- Verify that the octal output is 755.
- Switch the target if a file type is required.
Enter the final 9-character or 10-character Permission notation rather than a differential Operation such as u+x.
Break down ls -l output
| Display | Type | Permission | Octal |
|---|---|---|---|
| -rwxr-xr-x | File | rwx r-x r-x | 755 |
| drwxr-xr-x | Directory | rwx r-x r-x | 755 |
| -rw-r--r-- | File | rw- r-- r-- | 644 |
| -rw------- | File | rw- --- --- | 600 |
Read Owner, Group, Other, and 4, 2, and 1 separately.
The three Permission digits are Owner, Group, and Other from left to right. Each digit is octal, not decimal; add read=4, write=2, and execute/search=1. 7 is rwx, 6 is rw-, 5 is r-x, and 4 is r--. The first character of ls -l is the File Type, so do not include the leading - in -rw-r--r-- in the numeric value.
| Values | Symbols | Permissions |
|---|---|---|
| 0 | --- | None |
| 1 | --x | execute / search |
| 2 | -w- | write |
| 3 | -wx | write + execute |
| 4 | r-- | read |
| 5 | r-x | read + execute |
| 6 | rw- | read + write |
| 7 | rwx | read + write + execute |
For ordinary files, x is execute permission; for directories, x is search permission that allows reaching entries below by name. In a directory, r alone may reveal names in a listing, but without x, cd and access to child entries fail. If chmod alone does not resolve the issue, also check the owner/group, parent directories, ACLs, SELinux/AppArmor, mount options, and the application's execution user.
Troubleshooting when it does not work as expected
If conversion results are offset, check whether the leading type character was counted as the owner's r, or whether nine characters were shifted before splitting.
Check not only the target entry's mode but also the execution user, group, and parent directory with whoami, id, and ls -ld. If the symptom disappears only with sudo, do not broaden permissions to 777; review ownership and the service user. ACLs, SELinux, AppArmor, read-only mounts, noexec, interpreters, and line endings are separate factors.
- Check whether the character count is 9 or 10.
- Separate every three characters.
- Treat s/S/t/T as special Bits.
- For l and similar entries, enter only the permission portion
Supported scope of the current chmod permission calculator
The current DevelopTools tool converts among 3- and 4-digit octal values from 000 to 7777, the 9-character rwxr-xr-x notation, and 10-character ls -l-style notation starting with - or d. It can also specify Owner, Group, and Other r/w/x permissions and Setuid, Setgid, and Sticky bits through checkboxes, and displays octal notation, symbolic notation, numeric-mode chmod commands, explanations, and safety notes. Input is processed only in the browser and is not sent to a server.
| Function | Current tool operation |
|---|---|
| Input | Octal values such as 644, 0755, and 4755; rwxr-xr-x, -rw-r--r--, drwxr-xr-x, and checkboxes |
| Special bits | Setuid=4, Setgid=2, Sticky=1, and s/S/t/T display based on the execute Bit |
| Target | Select a regular file or directory, then switch the display prefix to - or d |
| output | Octal, Symbolic Permission, chmod numeric Command, permission descriptions, and Security Warning |
| Supplementary | Preset, Copy, Reset, recursive-application Warning, and cautions for private keys and 777 |
| Not implemented | Symbolic Operations such as u+x, g-w, and X; umask calculation; Binary display; File Types such as l; ACL / SELinux determination; actual File operations |
For articles covering unimplemented items, explain GNU chmod and Git command examples and decision procedures. The tool checks candidate final modes numerically or as rwx, but does not read the current mode to calculate differences, perform file-system operations, or execute commands.
Perform final verification using official GNU, POSIX, and Git documentation
Numeric mode, symbolic mode, recursive processing, and symbolic link handling vary by OS and implementation, so check man chmod and official documentation for the runtime environment. In particular, do not rely on memory alone for the combination of -R and symlinks, preservation of setuid/setgid, conditions for X, or umask effects.
Example: convert -rw-r----- to 640
Except for the leading -, separate it into rw-, r--, and ---.
Because it is 6 / 4 / 0, the result is 640.
- Exclude Type
- Split into three groups.
- Add each digit
- Verify 640 with the Tool
Octal may also be written as 0755 with a leading 0 as a string.
Frequently asked questions
- What does chmod 755 mean?
- Owner has rwx, while Group and Other have r-x. For a regular File, the owner can read, write, and execute, while others can read and execute. For a Directory, x acts as search permission.
- Will Permission denied be fixed by setting 777?
- If insufficient permissions are the only cause, it may change the result, but granting write and execute permissions to everyone is not a general solution. Identify the Owner, Group, parent Directory, and required operation.
- What is the difference between chmod and chown?
- chmod changes mode bits, while chown changes the owner or group. Even with the correct mode, access can fail if the executing user is not the expected owner or group.
- Can I run the chmod command shown by the tool as-is?
- Before use, check the target Path, current Mode, Owner/Group, File type, and scope beneath it on your device. The tool does not inspect actual Files or OS Access Control.