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Chmod Calculator

Convert Unix file permissions between octal and symbolic form.

Common permissions

Commands

chmod 755 file.txt

Breakdown

WhoReadWriteExecuteDigit

Bit meaning

4

read

2

write

1

execute

Read is 4, write is 2, execute is 1, and the three add together per group: read plus write is 6, so rw- is 6. 644 is the safe default for a file and 755 for a folder or script. 777 grants everyone full control and is almost never what you want.

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What Is Chmod Calculator?

The Chmod Calculator turns a Unix permission number such as 755 into the letters a listing shows, and back again. Enter an octal value or click the read, write, and execute checkboxes for user, group, and other, and the rwx form updates as you go.

Who Uses the Chmod Calculator?

Administrators use it to decode a mode from ls output or an SSH session, and to build the right value for chmod, chown, or a Dockerfile. It also covers the leading digit for setuid, setgid, and the sticky bit.

How to Use the Chmod Calculator

  1. Enter an octal mode like 755, or tick the individual permission boxes.
  2. Read the rwx result and the plain English meaning of each group.
  3. Copy the value into your chmod command.

Why Choose Our Chmod Calculator?

  • Both directions, octal to rwx and back
  • Setuid, setgid, and sticky bit support
  • Plain English explanation of every digit

Try the Chmod Calculator above — it is free, fast, and works on any device. Bookmark this page to return whenever you need it.