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Protect PDF

Add a password to a PDF so only people who know it can open it. The file is locked with AES‑256, the strongest standard PDF encryption, and you can also stop people printing, copying or editing it. The password is never sent anywhere: the PDF is protected right here in your browser.

Your files are processed in your browser and never leave your device.

How to use Protect PDF

  1. Click "Select PDF file" and choose the PDF to protect.
  2. Type a password and type it again to confirm it.
  3. If you like, open "More options" to limit printing, copying or editing.
  4. Click "Protect PDF" and download the protected file. Keep your password safe.

How to password protect a PDF for free

Choose your PDF, type a password twice, and click "Protect PDF". The new file asks for the password whenever someone opens it, in Adobe Acrobat, Preview on a Mac, web browsers and phone apps alike. A long password that mixes letters, numbers and symbols is much harder to guess; the strength hint helps you pick one.

There is no need for Adobe Acrobat or any other software. Everything happens in your browser, so both the document and the password stay on your device.

How to protect a PDF from copying, printing or editing

Open "More options" and untick what people shouldn't do: printing, copying text and images, editing, or filling in forms. Mainstream PDF readers respect these limits, but some programs ignore them, so treat them as a clear "please don't" rather than a lock. The password to open the file is the real protection.

You can also set a second password that lifts the limits. If you leave it empty, nobody can lift them later, not even you, so keep your original, unprotected file.

What if the protected PDF won't open?

A protected PDF opens only with exactly the right password. If it doesn't open, check these.

  1. Passwords are case-sensitive: check capital letters, spaces and the keyboard language.
  2. Very old PDF readers, from before about 2011, may not open AES-256 files: update the reader, or open the PDF in a web browser.
  3. If the password is forgotten, the file can't be opened: use your original, unprotected file and protect it again.
  4. "Can't be protected again": the file already had protection. Remove it with Unlock PDF first.

Frequently asked questions

Is my PDF or password sent to a server?

No. The PDF is encrypted inside your web browser, on your own computer or phone. Neither the document nor the password is ever sent to us or anyone else, and nothing is stored.

How secure is the password protection?

The file is encrypted with AES-256, the strongest encryption in the PDF standard, so the contents can't be read without the password. How safe it is in practice depends on your password: a long one with letters, numbers and symbols is far harder to guess than a short word.

What if I forget the password?

Then nobody can open the protected PDF, not even us: we never see or store your password, and there is no back door. Keep your original, unprotected file somewhere safe, or write the password down.

Which programs can open the protected PDF?

Any modern PDF reader: Adobe Acrobat Reader, Preview on Mac, Chrome, Edge, Firefox and Safari, and the built-in viewers on iPhone and Android. Very old readers from before about 2011 may not support AES-256 encryption.

Do the printing and copying limits really stop people?

Mainstream readers such as Adobe Acrobat respect them, but some programs ignore them, so they are a deterrent rather than real protection. If the content must stay private, rely on the password to open the file.

Does protecting a PDF change its quality?

No. The pages, text and images stay exactly the same; only the encryption is added. The file size stays about the same too.

Can I password protect a PDF on my iPhone?

Yes. It works in Safari and Chrome on iPhone and Android. Choose the PDF from your Files app, type the password, and the protected file is saved back to your phone.

Can I protect a PDF that already has a password?

Not directly. Remove the existing protection first with Unlock PDF (you need its password if it asks for one), then protect the unlocked copy here with your new password. Open Unlock PDF

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