Password protect a PDF without Acrobat: 5 free ways compared

By the getPDF team · Published 11 October 2026

The short answer

You do not need Acrobat. The quickest route on any system is getPDF’s Protect PDF: drop the file, type a password, download; it applies AES-256 in your browser and nothing is uploaded. On a Mac, Preview does it built in. If you are writing the document in Word or LibreOffice, set the password when you export the PDF. 7-Zip puts an encrypted archive around the file instead.

Try it here, nothing is uploaded

Drop a PDF to protect

PDF · any size

The 5 routes at a glance

Checked on 11 October 2026. “Cipher” is what the PDF ends up with; where the maker does not say, the table says so, and Inspect will tell you for your own result.

Route	Runs on	Cipher	Steps	The catch
getPDF Protect PDF	Any browser: Windows, Mac, Linux, phones	AES-256, revision 6	Drop, type, Protect, download	You need a browser that loaded the tool once; then it works offline
macOS Preview	Mac only	Apple does not name it	File, Export, Permissions	Mac only; check the revision with Inspect
LibreOffice PDF export	Windows, Mac, Linux	AES-256 with PDF 2.0 export, since LibreOffice 25.8	Export as PDF, Security tab	Only for documents you export from LibreOffice; older versions write RC4
Word’s PDF export	Windows (Microsoft 365, Office)	We found no Microsoft statement of the cipher	Save As, PDF, Options	Only for Word documents; protects the export, not an existing PDF
7-Zip archive	Windows (other systems via other unzip tools)	AES-256 on the archive	Add to archive, password	The PDF inside has no password once extracted

getPDF Protect PDF: any system, nothing uploaded

Open Protect PDF and drop the PDF, or several.
Type a Password to open. Leave Owner password empty unless you also want restrictions on printing or copying; then give it a different value (see user vs owner password for why).
Press Protect, then Download PDF. The file is saved as yourfile-protected.pdf.

What happens inside: the tool encrypts every piece of text and every stream with AES-256 and the standard’s own key derivation (revision 6, from ISO 32000-2), then opens the result again with your password to check it before you download. On our test files it took 0.2 seconds for a 3-page invoice and 1.6 seconds for a 500-page report on a mid-range laptop. A PDF that already has a password works too: the tool asks for it, and the result carries only the new one. The password is turned into a key inside a worker in your tab; the site has no server that could receive it, and its content security policy only allows connections to its own address.

It also works on a phone: open the page in the browser, pick the file from Files, and save the result.

macOS Preview: built in, Mac only

Apple’s Preview guide describes the steps (checked on 11 October 2026):

Open the PDF in Preview and choose File > Export. Give it a new name if you want to keep an unprotected original.
Click Permissions.
Tick Require Password To Open Document and type the password twice.
Set an owner password, and tick what readers may do without it.
Click Apply, then Save.

To change it later, File > Edit Permissions. Apple’s guide does not say which cipher Preview uses. If it matters, drop the result into Inspect: revision 6 is current AES-256.

LibreOffice and Word: protect at export

If the PDF does not exist yet because you are writing the document, set the password in the export dialog and you skip a step.

LibreOffice: File > Export as PDF, the Security tab, Set Passwords. LibreOffice 25.8 (August 2025) added PDF 2.0 export, which brings AES-256 encryption with it, as its release coverage notes. Older versions wrote 128-bit RC4, per LibreOffice’s own Ask forum in 2020, so update first and choose PDF 2.0 as the version in the export dialog.

Word on Windows: File > Save As, choose PDF as the type, click Options, tick Encrypt the document with a password, type it twice. Microsoft’s help pages we found do not name the cipher, so check the result with Inspect if you need certainty.

Both routes only help for documents you author there. An existing PDF, a scan or a bank statement needs one of the other routes.

7-Zip: encrypt the box, not the PDF

7-Zip (version 26.04 as of 5 October 2026) offers AES-256 for both its own 7z format and ZIP. Right-click the file, 7-Zip > Add to archive, type a password under Encryption, and choose AES-256. In the 7z format you can also tick encrypt file names, so even the list of files stays hidden.

That is genuinely the better answer in 2 cases: many files at once, and files whose names are themselves sensitive. The catch: the PDF inside is an ordinary PDF. Once the recipient extracts it, it has no password, and copies of it travel unprotected. Not every built-in unzip tool reads AES-encrypted ZIP files, so the recipient may need 7-Zip or a similar tool.

Which one to pick

Any existing PDF, any device: getPDF Protect PDF.
On a Mac and the file is open anyway: Preview, then Inspect to confirm the revision if strength matters.
You are still writing the document: the export dialog in LibreOffice 25.8 or later, or Word.
A folder of files, or secret file names: 7-Zip with AES-256.

Whichever you choose, send the password by a different channel than the file: a text message or a call, never the same email. Sending a confidential PDF by email covers the rest of that job.

Inspect PDFFonts, images, metadata, why it is big. Free, runs on your device.

The honest part

Windows 11 has no built-in way to put a password on a PDF. Microsoft Print to PDF writes files without one.
“Free online” tools that upload get your file before it is protected, and your password with it. They delete files after a set time, but you cannot check that. getPDF runs in your browser instead: run a tool once, turn Wi-Fi off, and it still works, because there is nothing to send.
A password is only as strong as its length. 4 or 5 random words hold up; a name and a year do not, whatever the cipher. How strong PDF encryption is has the numbers.
Restrictions such as no printing are a request to the viewer, in every one of these tools. Many programs ignore them, ours included.
If the PDF is digitally signed, any route that rewrites it breaks the signature, and getPDF warns when it writes a new copy of a signed file.

More free tools, compared honestly, are in the best free PDF tools; the full privacy picture is in the PDF privacy and protection guide.

Questions

Can Windows 11 password protect a PDF on its own?

No. Microsoft Print to PDF has no password setting. On Windows you need a tool: getPDF in the browser, Word's PDF export if the source is a Word file, LibreOffice, or 7-Zip around the file.

Is the free route as strong as Acrobat?

getPDF writes AES-256 at revision 6, the same scheme Acrobat X and later writes. For the other routes, drop the result into Inspect: revision 6 means the same strength.

Is it safe to use an online tool to add a password?

Only if the file never leaves your device. A tool that uploads gets the file before it is protected, plus the password. getPDF runs in your browser; turn Wi-Fi off after the first run and it still works.

Should I zip the PDF with a password instead?

For several files at once, or when file names must stay private, a 7-Zip archive with AES-256 is a good choice. The recipient needs an unzip tool that reads AES, and once extracted the PDF has no password.