How to Password-Protect a PDF for Free
To password-protect a PDF for free, upload it to myoffice, open the file's menu, choose PDF Tools…, then Protect (add password), and enter the password that will be required to open the file. The tool creates a new encrypted PDF using AES-256 encryption. You need a free account, and nothing needs to be installed.
Below are the steps, the difference between the two password fields, how to remove a password you already know, and a few habits that keep a protected file genuinely safe.
How do I add a password to a PDF?
- Sign in or create a free account, then upload the PDF (up to 50 MB).
- Open the file's ⋮ menu and choose PDF Tools….
- Select Protect (add password).
- Enter Password required to open. This is the one people will type to view the file.
- Optionally enter an Owner password. If you leave it blank, it defaults to the same as the open password.
- Start the job. When it finishes, the protected PDF appears in your folder.
Try opening the new file straight away and confirm it asks for the password. Keep the unprotected original somewhere safe until you have checked.
What is the difference between the open password and the owner password?
- The open password (also called the user password) is needed to open and read the document.
- The owner password is a separate credential that identifies who controls the file. It is set independently so the person managing a document can differ from the people who read it.
For most everyday cases, a single strong password is enough, which is why the owner field defaults to the same value.
How strong is the encryption?
The tool uses AES-256, the strongest encryption standard defined for PDF (the "revision 6" security handler). Encryption of this strength is not practically breakable by guessing the algorithm. The real weak point is the password you choose. A short or predictable password can be guessed, however strong the encryption is.
How do I choose a good PDF password?
- Length beats cleverness. A long passphrase of several unrelated words is stronger and easier to remember than a short jumble of symbols.
- Never reuse a password from your email, bank or other accounts.
- Share the password separately from the file. Send the PDF by email and the password through a different channel, such as a message or phone call.
- Store it in a password manager, because there is no way to recover an AES-256 protected PDF if the password is lost.
How do I remove a password from a PDF?
If you know the current password, removing it takes a minute:
- Open the protected file's menu and choose PDF Tools….
- Select Unlock (remove password).
- Enter the current password.
- Start the job. A new, unlocked copy is created.
This is for files you are entitled to open. It requires the correct password. If the password is wrong, the job fails, and the tool does not try to guess or break passwords.
Password protection versus other ways to secure a PDF
| Goal | Best approach |
|---|---|
| Stop casual access if a file is emailed to the wrong person | Password-protect the PDF |
| Mark a draft or confidential file | Add a watermark, such as CONFIDENTIAL |
| Share only some pages | Extract those pages into a new PDF first, then protect that |
| Remove sensitive information for good | Delete the pages or content before sharing. A password does not remove data, it only locks it. |
Frequently asked questions
Is it safe to upload a PDF to protect it?
Uploads are scanned for malware, stored in your own account area and not sold or mined. For highly sensitive documents, protect the file, download it, and delete the original and any unneeded copies from your storage.
Can I recover a PDF if I forget the password?
No. AES-256 encryption is designed so the file cannot be opened without the password. Keep the password in a password manager and keep a backup of the unprotected original if that is appropriate.
Will the protected PDF open in any PDF reader?
Yes. Password-protected PDFs using standard encryption open in mainstream PDF readers, including browsers, which will prompt for the password.
Can I protect a Word or Excel file?
This tool protects PDFs. To protect a Word or Excel document, export it to PDF first, then apply the password.
Try it
Create a free account, upload a PDF and add a password. You can also merge, split and reorder the same file before you lock it.