Password Protect PDF

No file size limits, no ad watermarks - A simple and secure web app to encrypt your PDF files with strong AES 128-bit encryption for free. Add password security to your PDF files in 5 easy steps.

TLS encryption for secure file processing
Password-protect PDF files with encryption
Quick to protect, near impossible to break

Reliable PDF Password Protection

Prevent unauthorized access to your file’s contents through encrypted password protection. The best method for sharing sensitive information with others securely.

No Data Retention

Smallpdf doesn't save any document passwords and files are permanently deleted after one hour. All data transfers are handled through TLS encryption to ensure the safety of your data.

On Mac, Windows, and Linux

As a web application, Smallpdf can be accessed using a Mac, Windows, or Linux machine, or even a mobile device. Just open your browser to add a document open password to your PDF!

Secure Encryption for Maximum Safety

Some PDF passwords can be hacked easily. With our AES 128-bit encryption, it would take thousands of years to crack your password with a regular computer.

Password Strength for Added Security

The more complex your password, the safer your file is from unauthorized changes. We recommend using a non-dictionary word of at least 7 characters with numbers, capital letters, and symbols.

Password-Protection in the Cloud

You don't need any software to use Smallpdf's online services. You can protect your PDF with a password by simply uploading it, choosing a strong password, and then downloading the password-protected PDF.