Number bases and chmod
Binary, hex and Unix permissions
Base conversion
0b, 0o, 0x prefixes and "_" separators accepted. No size limit.
8 bit(s)
chmod calculator
| Read | Write | Execute | |
|---|---|---|---|
| Owner | |||
| Group | |||
| Others |
Command
chmod 755 fileAbout this tool
The first part converts an integer between bases 2, 8, 10 and 16: edit any field and the other three update. It accepts 0b, 0o and 0x prefixes, spaces and underscore separators, so you can paste a value straight from code. Calculations use BigInt, so there is no size limit, and the tool shows how many bits the value needs.
The second part is a chmod calculator. Check read, write and execute permissions for owner, group and others, plus the setuid, setgid and sticky bits, or type an octal value such as 755 or a symbolic string such as rwxr-xr-x directly. The tool shows both forms along with the matching chmod command, ready to copy.
How to use it
- Under “Base conversion”, type a number into “Binary (base 2)”, “Octal (base 8)”, “Decimal (base 10)” or “Hexadecimal (base 16)”.
- Check “Uppercase hexadecimal” if you need it and copy any value with the button next to its field.
- In the “chmod calculator”, tick “Read”, “Write” and “Execute” for “Owner”, “Group” and “Others”, or fill in the “Octal” or “Symbolic” field.
- Add any “Special bits” you need, then copy the “Command”.
Frequently asked questions
Is there a size limit on numbers?
No. Conversions rely on JavaScript’s BigInt type, which handles integers of any size without losing precision. Only whole numbers are accepted; decimal fractions are not converted.
Are negative numbers supported?
Yes, with a minus sign in front of the value, in any base. The result keeps the sign, so -255 becomes -ff in hexadecimal. The tool does not produce a two’s complement representation.
What do s, S, t and T mean in permissions?
They mark special bits in place of the x: s for setuid or setgid, t for the sticky bit. Uppercase means the special bit is set without execute permission. With any of these bits, the octal value grows to four digits, such as 4755.
Can I paste the output of ls -l?
Yes. The symbolic field accepts nine characters such as rwxr-xr-x, or ten with the file type first, such as drwxr-xr-x or -rw-r--r--. The checkboxes and octal value update right away.