To password protect a PDF, open the Protect PDF tool, add your file, type a password twice and click protect. The new file asks for the password every time someone opens it.
The tool uses AES-256 encryption and runs on your device, so neither the document nor the password is sent anywhere.
On this page
Key takeaways
- The protected file uses AES-256 encryption and a password you choose.
- You can also block printing, copying or editing with three checkboxes.
- The password cannot be recovered, so store it safely.
- A PDF that is already protected has to be unlocked before you can protect it again.
How to protect a PDF in three steps
- 1
Add your PDF. Open Protect PDF and drop the file in.
- 2
Set the password. Type it in the Password field and again in Confirm password. If the two do not match, the tool asks you to correct them.
- 3
Protect and download. The new file is named like the original with -protected added. Open it to confirm that it asks for the password.
Choosing a good password
- Use at least 12 characters. Length matters more than symbols.
- A phrase of four or five unrelated words is strong and easy to remember.
- Do not reuse a password from another account.
- Send the password through a different channel than the file, for example by message instead of in the same email.
Optional permissions
Three checkboxes control what a person who has opened the file may do: print it, copy text and images, or edit it. All three are ticked by default. Untick one to restrict it. How these restrictions work, and where they stop working, is covered in PDF permissions explained.
Your file stays on your device
The encryption engine runs inside the page. The document and the password are never uploaded, which matters for contracts and personal paperwork. For a closer look at how strong this protection is, see how secure is PDF password protection.
Things to do first or after
- Trim the document first with Remove Pages or Extract Pages so only the right pages are in the protected file.
- Shrink it with Compress PDF before you protect it.
- Remove the password later with Unlock PDF if you know it.
When to protect a PDF
- Sending a contract, payslip, tax document or ID copy by email.
- Storing personal paperwork on a shared computer or cloud drive.
- Handing a file to a client or colleague who should be the only person to open it.
- Sharing drafts that are not yet public.
Protection is only as good as the way you share the password. Send it separately from the file, ideally through another app.
Protect PDF: FAQ
How do I password protect a PDF?
Add it to the Protect PDF tool, type a password twice, click protect and download the new file.
What encryption is used?
AES-256.
Is my PDF or password uploaded?
No. Everything happens in your browser.
Can I recover a forgotten password?
No. Keep the password and an unprotected original safe.
Can I protect a file that already has a password?
No. The tool asks you to unlock it first.
Can I stop people from printing?
Yes, by unticking Allow printing. See the permissions article for limits.
What is the output file called?
The original name with -protected added.
Can I protect several PDFs at once?
Yes, with one password. They download as a ZIP.
Will the password work in every PDF reader?
Modern readers support AES-256. Very old software may not.
Locked in a minute
Choose a strong password, protect the file and keep the password somewhere safe.
