Password Protect PDF Online Free

Secure your PDF with password encryption

Drop PDF to protect

Add password protection

Secure server processing. Files deleted after conversion.
Processed locally in your browser

Your files never leave your device. 100% private and secure.

How It Works

1

Select File

Upload the PDF you want to secure.

2

Set Password

Enter a strong password. This password will be required to open the file.

3

Encrypt

Click "Protect PDF" to apply encryption and download your secured document.

Frequently Asked Questions

How secure is the encryption?
We use industry-standard PDF encryption to protect your documents.
Can I set different permissions?
The current tool sets an open password. Advanced permissions may be added in future updates.
What if I forget the password?
Keep your password safe—there is no way to recover it. Always keep an unprotected backup.
Can protected PDFs be unlocked?
Only with the correct password. Use our Unlock PDF tool if you have the password.

About This Tool

Password protect PDF files with our free PDF encryption tool. Add password security to prevent unauthorized access to sensitive documents. Our PDF password protection uses industry-standard encryption to secure contracts, financial reports, confidential proposals, or personal documents. Recipients must enter the password to open the file. Perfect for securing PDFs before emailing or sharing. The browser-based encryption ensures we never see your documents or passwords – 100% privacy. Always keep your password safe; recovery is impossible without it.

Why Use AeroPDF?

100% Private & Secure

Files are processed entirely in your browser. Nothing is uploaded to any server.

Lightning Fast

No waiting for uploads or downloads. Everything happens instantly on your device.

Works Everywhere

Use on any device with a modern browser. Windows, Mac, Linux, or mobile.

Key Features

Strong industry-standard encryption
Prevents unauthorized opening of files
Zero knowledge: passwords stay on your device
Secure client-side processing
Simple and instant locking