Developer Tools
Chmod Calculator
Chmod Calculator is part of Toolspire and is ready as soon as this page loads. 4 is read, 2 is write, 1 is execute. 7 is all three. 5 is read and execute. 644 would be rw-r--r--. The page does not change any file.
On this page
What you can do here
Three groups
The detail names owner, group and others separately.
755 is the check
A directory people can enter and only the owner can change.
No file is touched
The page translates a number. It does not run chmod.
The sequence
How to use the Chmod Calculator
- 1
Add the bits
Read plus write is 6. Read plus execute is 5. All three are 7.
- 2
Check 755
It must read rwxr-xr-x.
- 3
Try 644
rw-r--r--. If you see an x, a digit included 1.
Worth knowing
- Chmod Calculator on Toolspire: 755 is rwxr-xr-x. Owner 7, group 5, others 5.
- 4 = r, 2 = w, 1 = x. A digit is the sum of the bits you want.
- 644 is rw-r--r--. Owner can write. Nobody can execute.
- The mode must be an integer from 0 to 777 with no digit above 7.
Three octal digits, three trios
A chmod mode is three octal digits. Each digit’s 4, 2 and 1 bits are read, write and execute for one class of user: owner, then group, then others. 7 is 4+2+1, so rwx. 5 is 4+1, so r-x. 755 is therefore rwxr-xr-x. A digit of 8 or 9 is not an octal permission and is rejected. Nothing on disk changes.
FAQ
Questions about Chmod Calculator
Where does Chmod Calculator run?
What is chmod 755 in letters?
What is 644?
What do 4, 2 and 1 mean?
Does this change a file?
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