chmod 644 — Default Permissions for Regular Files

This page opens the calculator preset to 644: the owner gets 6 (4 read + 2 write), group and others get 4 (read only), giving the symbolic notation -rw-r--r--. No one has the execute bit — this is a mode for data, not for programs.

644 is the default you want for almost every regular file on a server: HTML, CSS, images, application code that is interpreted rather than executed directly, and most configuration files. The web server user can read and serve the file, but cannot modify it — so even a compromised worker process cannot silently rewrite your pages. Together with 755 on directories, '644 for files, 755 for folders' is the classic permission scheme for WordPress and most PHP/static hosting.

If a file contains secrets — database passwords, API keys — 644 is too open, because any local account can read it: step down to 640 or 600 with the checkboxes and watch the notation update. And if you ever see a script fail with 'Permission denied' under 644, that is the missing execute bit, not a broken file.