How to Encrypt a PDF (Add Password Protection, Free)

To encrypt a PDF with a password, use a free online tool like Smallpdf or iLovePDF — upload the file, set a password, and download the encrypted version. For offline encryption, Microsoft Word’s “Encrypt with Password” feature also works if you have the original document. This is the same as password-protecting a PDF — tools use the two terms interchangeably.

Method 1: Online encryption (any device)

1. Go to Smallpdf Protect or iLovePDF Protect.
2. Upload the PDF.
3. Enter a strong password (12+ characters).
4. Choose permissions — allow or block printing and copying.
5. Click Protect / Encrypt and download the locked PDF.

Privacy note: Online tools process the file on their servers. For sensitive documents, use Method 2 offline.

Method 2: Microsoft Word (offline)

1. Open the document in Word.
2. File → Info → Protect Document → Encrypt with Password.
3. Enter and confirm the password, then Save As → PDF.

The exported PDF inherits the password. If the PDF needs edits first, convert it to Word, make your changes, then encrypt.

Method 3: Google Drive (workaround)

Google Drive can’t password-protect a PDF directly, but you can restrict who can view it by sharing the file privately (right-click → Share → “Restricted”). This isn’t encryption, but it controls access.

What encryption actually does

PDF encryption scrambles the file so it can’t be opened without the password. Two protection levels:

• Open password — required to view the file at all.
• Permissions password — allows viewing but blocks printing, copying, or editing.

FAQ

Is encrypting a PDF free?

Yes. Smallpdf and iLovePDF encrypt free with daily limits; Word does it offline with no limits.

What’s the difference between password-protecting and encrypting?

They’re the same for most tools — setting a password encrypts the file so it can’t be read without it.

Can I encrypt a PDF on my phone?

Yes. The Smallpdf and iLovePDF mobile apps both add password protection on iOS and Android.

What happens if I forget the password?

The PDF is unrecoverable without brute-force cracking. Store passwords in a password manager.