To password protect a PDF, select Select PDF, type a password in New Password and Confirm Password, choose a Permissions preset, and select Lock PDF. The locked copy downloads straight away and asks for that password when opened. It is encrypted with AES-256, and your original pages are kept, so text stays selectable.
How to password protect a PDF
- Add your PDF. Drag a PDF onto the drop area or select Select PDF. Up to 8 pages are previewed. If the file already has a password, you're asked for it first.
- Set the password. Type it in New Password and again in Confirm Password. It needs at least 3 characters. Add an Owner Password for changing permissions, or leave it empty and the tool generates one and shows it after locking.
- Choose permissions. View Only is the default. Pick Allow Printing, Allow Print + Copy, Standard or Full Access, or flip the individual switches.
- Lock it. Select Lock PDF. The protected file downloads as
yourfile-locked.pdf. Open it once to check the password works before you share it.
How strong is the PDF encryption?
The locked copy uses the PDF Standard security handler with 256-bit AES (revision 6, the method defined in PDF 2.0). The encryption is done in your browser with its built-in Web Crypto functions.
- Strength: AES-256 itself isn't the weak point. A short or common password is, because cracking tools try passwords, not keys. Use 12 or more characters, or a few unrelated words.
- Compatibility: Adobe Acrobat and Reader X and later, Chrome, Edge, Firefox and macOS Preview open these files. Very old PDF readers from before 2010 can't.
- Password length: up to 127 bytes count, which is plenty for any normal password, including spaces and non-Latin letters.
Encryption protects the file while it's stored or sent. Once someone opens it with the password, they can see everything in it, so share the password through a different channel than the file.
What changes in the locked PDF
With Page Handling on Keep original pages (the default), the pages are copied as they are. Text stays selectable and searchable, links keep working, and page sizes don't change. When you lock all pages, bookmarks and form fields come along too.
- Typing a Page Range such as
1-5,8builds a new file from just those pages. Bookmarks aren't carried over in that case. - If the PDF you load already has a password or permission restrictions, its pages are converted to images instead, because the browser library that copies pages can't read encrypted files.
- You can also choose Convert pages to images yourself. Pages keep their original size; Image Quality sets the JPEG quality and Image Resolution sets the sharpness (2x, about 144 ppi, by default). Text in image pages can't be selected.
If you only need fewer pages without a password, the PDF splitter does that.
Open password vs owner password
A PDF can carry two passwords. The open (user) password is the one people type to view the file. The owner password controls the permissions: printing, copying text and images, filling forms and adding notes, and (with Full Access) making changes.
| Permissions preset | Copy | Forms and notes | |
|---|---|---|---|
| View Only (default) | No | No | No |
| Allow Printing | Yes | No | No |
| Allow Print + Copy | Yes | Yes | No |
| Standard | Yes | Yes | Yes |
| Full Access | Yes | Yes | Yes, plus editing |
Permissions are honoured by apps such as Adobe Acrobat, but some viewers ignore them. If you leave Owner Password empty, the tool generates a random 20-character owner password and shows it once after locking, with a Copy button. Save it if you'll want to change the permissions later. The owner password has to be different from the open password, or anyone who can open the file could also change its permissions.
How to password protect a PDF file on Windows or Mac
If you'd rather use an app you already have, both Windows and macOS can add a password when they save a PDF.
Windows, with Microsoft Word
Open the document (Word can also open a PDF) and choose File › Export › Create PDF/XPS Document › Create PDF/XPS. Select Options, tick Encrypt the document with a password, select OK, enter the password and select Publish.
Mac, with Preview
Open the PDF in Preview and choose File › Export. Select Permissions, tick Require Password To Open Document, enter the password twice, set an Owner Password, then select Apply and Save.
Frequently asked questions
How do I password protect a PDF for free?
Load the PDF at the top of this page, enter and confirm a password, and select Lock PDF. It's free, needs no account, and the locked file is created on your device.
Is my PDF uploaded when I lock it?
No. The PDF is read, copied and encrypted in your browser. Neither the file nor the password is sent to ToolzyLab.
Can I lock a PDF that already has a password?
Yes. When you load it, the tool asks for the current password. After that you can set a new password and permissions and save a freshly locked copy.
Can I still select text in the locked PDF?
Yes, with Page Handling on Keep original pages. Text is only turned into images if you choose Convert pages to images, or if the PDF you loaded was already encrypted.
What if I forget the password?
Keep the original unprotected file somewhere safe. ToolzyLab never sees your password, so it can't be recovered or reset for you.
Can I encrypt a PDF with AES-256 here?
Yes. Every locked copy is encrypted with 256-bit AES, the strongest method in the PDF standard. There's no weaker option to choose by mistake.
How do I remove the password later?
Use the PDF password remover and type the password when asked. It saves a copy that opens without one.