umask Calculator for Linux & macOS

See what permissions new files and folders get under any umask, then open the result in the chmod calculator.

Type or paste any notation — octal, symbolic, chmod command, ls -l output or relative changes like u+x.

Permissions

	Read (4)	Write (2)	Execute (1)	Octal
Owner (u)				6
Group (g)				4
Others (o)				4

Octal

644

Symbolic

rw-r--r--

ls -l

-rw-r--r--

symbolic cmd: decimal: 420binary: 000 110 100 100

What 644 means on a file

Owner can read, modify.
Group can read.
Others can read.

Change from an existing mode

644

Already the same — nothing to change.

Commands & code

chmod (octal)

chmod 644 file

chmod (symbolic)

chmod u=rw,go=r file

Check current mode

stat -c '%a %A %n' file   # Linux
stat -f '%Lp %Sp %N' file  # macOS

Dockerfile

COPY --chmod=644 file /app/file

Ansible

ansible.builtin.file:
  path: file
  mode: "0644"

Kubernetes volume

defaultMode: 420  # = 0644 (JSON needs decimal)

Terraform (local_file)

file_permission = "0644"

Python

import os
os.chmod("file", 0o644)

Node.js

import { chmodSync } from "node:fs";
chmodSync("file", 0o644);

os.Chmod("file", 0644)

Rust

use std::os::unix::fs::PermissionsExt;
std::fs::set_permissions("file", std::fs::Permissions::from_mode(0o644))?;

Common permissions

umask calculator

umask

New files start from 666 and directories from 777; the umask removes bits. Check yours with umask, set it in ~/.bashrc or a systemd unit's UMask=.

Loading Tool...

Help shape umask Calculator for Linux & macOS

The bug you just noticed will fade in 3 minutes. The feature idea will vanish after your next tab switch. Crazy peps don't suffer silently.

0/1000

Discord Contribute

Frequently Asked Questions

New files start at 666 and directories at 777; umask removes bits. 022 gives 644 files and 755 directories.

022 for personal machines, 002 for shared group projects, and 077 when files should be private by default.

Run umask 027 in a shell, add it to ~/.bashrc or ~/.zshrc, or set UMask= in a systemd unit.

No. It only affects files and folders created afterwards — use chmod for existing ones.

Continue with a nearby utility

Chmod Calculator — Linux File Permissions Made Clear

chmod 755 Explained (rwxr-xr-x)

chmod 644 Explained (rw-r--r--)

Cron Expression Explainer, Builder & Tester

Frequently Asked Questions