Password Protect PDF — Add a Viewing Password
Add a password to your PDF so it cannot be opened by anyone who doesn't know it. Useful for sending sensitive documents by email or storing them in shared drives.
View-open password
The password protects opening the file. Once opened, the content can be read, printed and copied as usual.
Choose a strong password
A short password can be brute-forced quickly. Use at least 12 characters mixing letters, numbers and symbols — or use the Password Generator tool.
Free, with no file limits or sign-up
Many sites that offer to password protect a PDF for free cap the file size, add a watermark or ask for an email before the download. Here the encryption runs in your browser, so there is no account, no daily quota and no watermark on the output. Protect as many PDFs as you need.
How the protected file behaves
The output opens in Adobe Acrobat, Chrome, Edge, Firefox, macOS Preview and mobile PDF apps, and each one asks for the password before showing any page. The page content is encrypted inside the file, so renaming it or opening it in another program does not bypass the prompt.
Frequently Asked Questions
If I lose the password, can I recover the file?
No. That's the point of encryption. Store your passwords in a password manager.
Does the password stop copying or printing?
This tool only sets an open-password. Fine-grained permissions (no printing, no copying) require desktop software like Acrobat.
Is the encryption strong?
Modern AES-256 encryption via pdf-lib — same standard used by government and enterprise PDFs.
Can I password protect a PDF on my phone?
Yes. The tool works in mobile Chrome and Safari. Pick the PDF from your files, set the password, and the protected copy is saved to your downloads.
Does protecting a PDF change its size or quality?
No. Text, images and layout stay exactly the same; encryption adds only a few kilobytes.
Can I protect a PDF that already has a password?
Remove the existing password first with the Unlock PDF tool (you need to know it), then set the new one here.