Chmod Calculator

Convert between octal and symbolic Unix file permission notation

GET 1 credit /v1/chmod-calc

curl "https://devtools.toolkitapi.io/v1/chmod-calc?mode=755"

import httpx

resp = httpx.get(
    "https://devtools.toolkitapi.io/v1/chmod-calc?mode=755",
)
print(resp.json())

const resp = await fetch("https://devtools.toolkitapi.io/v1/chmod-calc?mode=755", {
});
const data = await resp.json();
console.log(data);

# See curl example

Response 200 OK

{
  "octal": "755",
  "symbolic": "rwxr-xr-x",
  "numeric": 493,
  "owner": {"read": true, "write": true, "execute": true},
  "group": {"read": true, "write": false, "execute": true},
  "others": {"read": true, "write": false, "execute": true}
}

Try It Live

Description

Convert between octal and symbolic Unix file permission notation

How to Use

1

1. Pass a permission mode in the `mode` query parameter. - Octal: `755`, `644`, `0777` - Symbolic: `rwxr-xr-x` (9 chars) or `-rwxr-xr-x` (10 chars with file type prefix)

2

2. Inspect the response for both octal and symbolic representations plus the per-class breakdown.

About This Tool

Chmod Calculator converts between octal (e.g. `755`) and symbolic (e.g. `rwxr-xr-x`) Unix file permission notation. It breaks down each permission class — owner, group, and others — into individual read, write, and execute flags.

Pass either format and get back both representations plus the decimal numeric value and per-class permission details.

Why Use This Tool

Server hardening — Verify file permissions match security requirements
Deployment scripts — Convert between formats when writing chmod commands
Documentation — Generate human-readable permission breakdowns for runbooks
Code review — Quickly decode octal permissions in Dockerfiles or config management scripts

Frequently Asked Questions

Does it support setuid/setgid/sticky bit?

The symbolic parser recognises `s`, `S`, `t`, and `T` characters but special bits are best handled via 4-digit octal (e.g. `4755` for setuid).

Can I pass a 10-character symbolic string?

Yes. A leading file type character (e.g. `-rwxr-xr-x` or `drwxr-xr-x`) is stripped automatically; only the 9 permission characters are used.

What's the `numeric` field?

The decimal (base 10) representation of the permission bits. For `755` octal, this is `493` decimal.

Start using Chmod Calculator now

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