What does chmod 755 mean?

755 gives the owner read, write and execute (7 = 4+2+1), and the group and other read and execute only (5 = 4+1). It is the typical permission for directories and executable scripts.

How is the octal value calculated?

Each scope adds read (4), write (2) and execute (1). So read plus write is 6, read plus execute is 5, and all three is 7. The three digits are owner, group and other in that order.

Does this tool send my permissions anywhere?

No. The calculator runs entirely in your browser, so nothing you select or copy is uploaded.

Chmod Calculator

Tick read, write and execute boxes — get the octal chmod command.

Chmod calculator — octal and symbolic permissions

Stop guessing chmod numbers. Tick read, write and execute for owner, group and other and instantly get the octal value (like 755), the symbolic notation (rwxr-xr-x) and the exact chmod command to copy and run. Presets cover the everyday cases — 644 for files, 755 for executables and directories, 600 for private files.

Everything runs in your browser; nothing is uploaded.