Password Protect PDF Free Online
Add a real, standard PDF password — the kind every PDF reader recognizes with a password prompt. Everything happens locally in your browser; your file and password are never uploaded.
Drag & drop a PDF here or
Why protect PDFs with One Page PDF Converter?
Most free "password protect PDF" tools upload your document to a remote server to add the password — which is a strange thing to do with a file you're specifically trying to keep private. This tool works differently: encryption happens entirely inside your browser using the standard PDF security format, so your file and your password never travel over the network.
This produces a real, standard-compliant encrypted PDF (128-bit AES, the same method Adobe Acrobat has used since 2005) — not a proprietary format only this site can open. Anyone with the password can open it in Adobe Reader, Preview, Chrome, or any other standard PDF viewer.
Common ways people use this tool
- Protecting a contract or financial document before emailing it
- Adding a password to tax documents or pay stubs before storing or sharing them
- Restricting access to an internal report before wider distribution
- Securing a document containing personal or medical information
Frequently Asked Questions
How do I password protect a PDF for free?
Add your PDF above, type a password, and click Protect & Download. The downloaded PDF will prompt for that password whenever anyone tries to open it, in any standard PDF reader.
Will the protected PDF open in Adobe Acrobat and other PDF readers?
Yes. This uses the standard PDF password encryption format (128-bit AES, the same method Adobe Acrobat has used since 2005), so the file opens with a normal password prompt in Adobe Reader, Preview, Chrome, and any other standard PDF viewer — not just on this site.
Is my PDF uploaded to a server?
No. Encryption happens entirely inside your browser. Your file and your password are never sent over the network.
What happens if I forget the password?
There is no way to recover a forgotten password or open the file without it — that's what makes the encryption real. Keep your password somewhere safe.