Free · No signupRuns in your browserNo file size limit

Password Protect a PDF — Free, In Your Browser

Add a real password to a PDF before you email it. The file is encrypted in your browser with AES — the same standard desktop PDF software uses — and you can separately restrict printing, copying and editing.

Drop your PDF hereAdd a password and control printing, copying and editingProcessed on your device — never uploaded

How to password protect a PDF in 4 steps

1
Choose your PDF
Drop in the file you want to protect.
2
Set a password
Enter the password recipients will need to open it. Optionally set a separate owner password that controls permissions.
3
Choose permissions
Decide whether the document can be printed, copied from, edited or annotated once opened.
4
Download the locked PDF
Download the encrypted file, then send the password over a different channel from the document.

Worth knowing

Encryption happens locally — the password you type never travels anywhere.
Send the password by a different route than the file. A password in the same email as the attachment protects nothing.
There is no recovery. If you forget the password, the document cannot be opened — keep a copy of the original.

Your file never leaves this tab

The tool runs entirely in your browser. There is no upload, no server-side copy and no retention policy to take on trust — open your devtools Network tab and watch: nothing goes out.

Lock PDF FAQs

Is the password sent to a server?

Nothing is uploaded. The tool runs entirely inside your browser tab using WebAssembly and JavaScript — your file never crosses the network, so there is no server copy to leak, retain or subpoena. You can prove it: open your browser devtools, switch to the Network tab, and run the tool. No request goes out. The password is used to derive the encryption key locally and is never transmitted or stored.

What encryption is used?

AES, applied through the standard PDF security handler. Any PDF reader — Preview, Acrobat, Chrome, a phone — will prompt for the password and open the file normally once it is entered.

What is the difference between a user and an owner password?

The user password is required to open the document at all. The owner password governs permissions — printing, copying, editing. Set only a user password and anyone who can open the file has full rights over it; set both and you can allow opening while restricting printing or copying.

Can I remove a password with this tool?

No. This tool adds protection, it does not strip it. Removing a password requires knowing it, and we deliberately do not build that — it is the kind of feature that mostly gets used on documents the user does not own.

Is a password-protected PDF secure enough for legal documents?

For emailing a contract to a counterparty, yes — it prevents casual interception and accidental forwarding. It is not a substitute for a secure data room when you are handling regulated or highly sensitive material.

If the document itself is the problem

The app can password-protect a document at the moment you export it, so a sensitive contract is never briefly unprotected on your device.

The app also drafts a contract from your answers and reviews one you were sent, clause by clause. It is free to download and free every month for 3 documents and 2 reviews — this tool stays free either way.

What the app does →What it costs →