How to Password Protect a PDF File — Free Online Tool
Add encryption and password protection to any PDF document without uploading it to a server.
Sensitive documents deserve protection. Whether you're sharing financial statements, legal contracts, HR records, or medical documents, adding a password to your PDF ensures only authorized recipients can open it.
Our Add Password to PDF tool encrypts your documents using AES-256 encryption — the same standard used by banks and government agencies. The encryption happens entirely in your browser, so your unencrypted document never touches any server.
There are two types of PDF passwords: the user password (also called the open password) restricts who can open the document. Anyone without the password sees an error message. The owner password restricts specific actions like printing, copying text, or editing — even after the document is opened.
For maximum security, set both passwords and make them different. The user password protects access, while the owner password prevents unauthorized modifications. This is the standard approach for distributing confidential business documents.
Implementation is straightforward: upload your PDF, enter your desired password, and download the encrypted version. The original file remains unchanged on your device. You can verify the protection by trying to open the encrypted PDF — your PDF reader will prompt for the password.
Password strength matters. A weak password like "123456" can be cracked in seconds. Use a strong password with at least 12 characters, mixing uppercase, lowercase, numbers, and symbols. Our Password Generator tool can create strong, random passwords for exactly this purpose.
For documents you need to share with multiple people, consider using a shared secure channel to distribute the password — never include it in the same email as the PDF. A phone call, encrypted message, or separate secure communication is the best practice.
If you later need to remove the password (perhaps for an archived document you no longer need to restrict), our Remove PDF Password tool can decrypt the file — provided you know the current password, of course.