RemixPDF

Password protect a PDF, free

Add a password so the document cannot be opened without one, or remove a password you already know. Nothing to sign up for.

  • Put a password on it, or take one off.
  • Free
  • No signup
  • No watermark

Runs on your device

This tool is being built — the page below is a preview of what's coming.

What you have to hand while you work

Why it works

It controls who can open the file.

That is what a password does, and it is genuinely strong. What it does not do is hide anything from someone who has the password — once the document is open, everything in it is there.

There is no way to recover it.

We do not keep it, we cannot reset it, and a PDF with a lost password is a lost document. The tool says this before you set one, not after.

Removing one is here too, if you know it.

Type the password and the protection comes off. Without the password nothing can be done, by us or by anyone else, which is the point of it working.

There are two different things people mean by protecting a PDF, and conflating them is how documents leak.

The first is controlling who can open the file at all. That is a password, and it works — the contents are encrypted, and without the password there is nothing readable to find. This tool does that, and it also does the reverse: if you know the password on a document, you can take the protection off.

The second is stopping a particular person from seeing a particular thing inside a document that they are allowed to open. A password does nothing for that. Once the file is open, everything in it is available — every name, every figure, every comment left in the margin. If a name has to be gone, it has to actually be deleted from the file, which is a different tool and one we keep deliberately separate.

The warning that matters most here is about loss. A PDF password has no recovery mechanism: it is not an account you can reset, there is no email link, and we have no copy because encryption happens in your own browser. A document whose password is forgotten is a document nobody opens again. The tool says that before you set one and asks you to confirm, because the moment to hear it is not afterwards.

One more distinction worth being straight about. A PDF can also carry flags asking readers not to print or copy the file. We can set those, and most software honours them — but they are a request, not a lock, and software that ignores them is not doing anything clever. We will describe them as what they are rather than selling them as security.

Everything happens in this browser, including the encryption, so the password itself never travels. There is no signup, no limit, and no watermark.

How it goes

  1. Open the PDF.

    If it is already protected, it asks for the password at the door — as a real field, because you have the password.

  2. Choose to add or remove.

    Adding asks for a password twice; removing asks for the current one.

  3. Read the warning once.

    It says plainly that a lost password cannot be recovered, and asks you to confirm.

  4. Download it.

    The protected file is new. Your original is untouched.

What you can check for yourself

Watch the network while you work — nothing leaves this device on the default path. Then go offline and keep working — it all still runs. The two-minute checks live at how your files are handled.

Frequently asked questions

The document is gone. We do not store it, cannot reset it, and there is no recovery path. Keep it somewhere you trust before you set it.

No. Encrypting and decrypting happen in this browser, so the password is never sent anywhere. That is a consequence of how the tool works rather than a promise about our conduct.

No, and the difference matters. A password decides who can open the file. It does nothing about what is inside it once opened — if a name needs to be gone, that is the tool that permanently removes text, not this one.

A PDF can carry flags requesting that, and we can set them. They are a request rather than a lock — most readers honour them, some ignore them — and we will not describe that as protection.

Only if you know the password. Otherwise there is nothing to do, which is what makes the encryption worth having.

Standard PDF encryption, which is genuinely strong against guessing when the password is a good one and weak when it is "1234". The password is the variable, not the algorithm.

Related tools

Ready? Drop your PDF above and it opens right here.