How to Password Protect a PDF (and Unlock One You Can Already Open)
By the FreePDF team ·
Some PDFs shouldn't open for just anyone — a contract, a payslip, a client file. A password is the simplest way to make sure only the person you send it to can see what's inside, and adding one takes a few seconds.
Locking a PDF
- Open the Protect PDF tool and upload your file.
- Choose a password to lock the document.
- Download your password-protected PDF.
What the password actually does
The file is encrypted with AES-256, the same standard used for sensitive financial and medical documents. Without the correct password, the PDF simply won't open — there's no way around it, which is exactly the point.
- Nothing is stored on our end, not your password and not your file, so keep the password somewhere you won't lose it.
- If you forget it, there's no recovery option. That's the tradeoff for real encryption rather than a cosmetic lock.
Removing a password
Got a protected PDF, know the password, and tired of typing it in every time? You can strip the protection instead.
- Open the Unlock PDF tool and upload the protected file.
- Enter the file's current password.
- Download an unlocked copy that opens without prompting.
What this isn't for
This removes a password from a file you can already open — it isn't a way to crack or bypass a password on someone else's document. Only unlock files you own or have permission to access.
Common questions
What happens if I forget the password I set?
The file can't be recovered. We never keep a copy of your password or your PDF, so back up the password somewhere safe before you send the file anywhere.
Can this remove a password I don't know?
No. Unlocking requires the file's current password — it removes protection, it doesn't guess or crack one you've lost.