Add Password to PDF — Free Online Tool
Add a password to any PDF file online for free. Your files and passwords stay private — zero-knowledge encryption in your browser.
Set a password on any PDF file in seconds. Recipients will be prompted for the password before they can view the document. Choose a strong password and share it separately from the file for maximum security.
Drop PDF to password-protect
PDF • Max 200MB
How It Works
Add password protection to any PDF using AES-256 encryption — the industry standard used by banks and governments. The encryption process runs entirely in your browser using WebAssembly, so your PDF and password never leave your device.
Choose a strong password, confirm it, and download the encrypted PDF. Recipients will need the password to open the file. The original formatting, fonts, and images are preserved exactly.
Features
- ✓AES-256 encryption — military-grade security standard
- ✓Password-to-open protection prevents unauthorized access
- ✓Preserves all formatting, fonts, and embedded images
- ✓Handles PDFs up to 200MB
- ✓Zero-knowledge — your password never leaves your device
- ✓Compatible with all PDF readers (Adobe, Chrome, Preview)