How to password protect a PDF for free

Upload the PDF to Protect PDF, type a password twice, and download the protected file. Anyone opening it will be asked for the password. The file is encrypted with AES-128.

Step by step

1. Open the Protect PDF tool and upload your document.
2. Type the password you want, then type it again to confirm.
3. Click "Lock PDF" and download the protected copy.
4. Open the new file yourself to make sure it asks for the password and accepts the one you chose.
5. Send the file, and share the password by a different route, for example by phone or in a separate message.

Choosing a password that holds up

• Length matters more than cleverness: aim for 12 characters or more.
• Avoid names, birthdays and words from the dictionary on their own. A short phrase of several unrelated words is easy to remember and hard to guess.
• Do not reuse a password from an email or bank account.
• Never put the password in the same message as the file.

What the password does and does not do

The file is encrypted with AES-128, so the contents cannot be read without the password. The weak point is the password itself: a short or common one can still be guessed.

Anyone who has the password can open the file, print it and copy text from it. The password controls who can open the PDF, not what they do once it is open.

Before you rely on it

• Keep an unprotected original somewhere safe. If the password is lost there is no way to recover it from the protected file.
• The password is used only to protect the file while it is processed. It is never stored.
• To remove protection later, use the unlock guide. You will need the password.
• On a Mac, Preview can also encrypt a PDF: choose File, then Export, and tick the Encrypt box.

Frequently asked questions

Is it free to password protect a PDF?

Yes. Protecting a PDF is a free tool, within the free plan limits of 10 files a day and 25 MB per file.

How strong is the protection?

The file is encrypted with AES-128. Strength then depends on your password, so use a long, unique one and send it separately from the file.

What happens if I forget the password?

It cannot be recovered from the file. Keep the unprotected original or a record of the password in a safe place.

Can people still print and copy text?

Yes, once they have entered the password. The password decides who can open the file, not what they can do with it.

Do you keep my password?

No. It is used only while the file is being protected and is not stored.

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