How to Password Protect a PDF Free Online

Last Updated: September 2026

Password-protecting a PDF prevents anyone who doesn't have the password from opening, copying, or printing the document. This is essential for sending tax documents, legal contracts, medical records, or any file containing personal information.

The good news: you don't need Adobe Acrobat to do this. There are free options for every platform.

Method 1: Docuvory — Free Online PDF Password Protection

Go to Docuvory's Protect PDF tool.
Upload your PDF — drag and drop or click "Select PDF Files".
In the "Password" field, enter the password you want to set. Use a strong password: at least 12 characters, mixing letters, numbers, and symbols.
Click "Process".
Click "Download File" to save your password-protected PDF.

Docuvory applies 256-bit AES encryption — the same standard used by banks and government agencies. The password cannot be recovered or bypassed without a brute-force attack; choose a strong password and store it somewhere safe.

Important: Your original file (without the password) is not modified. Only the downloaded file has the password applied. The file is permanently deleted from Docuvory's servers within 1 hour.

Method 2: Adobe Acrobat Pro

Open your PDF in Acrobat Pro.
Go to File → Properties → click the Security tab.
In the Security Method dropdown, select "Password Security".
Check "Require a password to open the document".
Enter your password in the Document Open Password field.
Choose your encryption level — AES 256-bit is the current standard. Leave this as the default unless you need compatibility with very old PDF viewers.
Click OK, confirm the password, then File → Save.

Acrobat also lets you set permissions separately — you can allow opening without a password but require one to print or copy content. This is useful for distributing a document publicly while restricting redistribution.

Method 3: macOS Preview (Mac Only)

Open your PDF in Preview.
Go to File → Export as PDF.
In the export dialog, click "Show Details" (a small arrow at the bottom of the filename area).
Check "Encrypt".
Enter and verify your password.
Click Save.

Preview applies 128-bit AES encryption by default. This is secure for general use, but if you need 256-bit AES (required by some institutions), use Docuvory or Acrobat Pro instead.

What to Do If You Forgot the PDF Password

This is one of the most common questions about PDF security — and the honest answer is: it depends on the encryption strength.

If you know the password was simple or short

A short password (under 8 characters, all lowercase or all numbers) can sometimes be recovered using brute-force tools. However, this is a technical process, not a "click here" solution — it requires specialised software and can take hours or days depending on the password complexity.

If you set the password yourself and forgot it

Check your password manager first. If you use 1Password, LastPass, Bitwarden, or any other manager, search for the site or document name. Check your notes app and any cloud services where you might have written it.

If the PDF was sent to you with a password

Contact the sender. There is no legitimate way to bypass a properly encrypted PDF without the password. Any service claiming to "unlock any PDF instantly for free" either only works on weakly-encrypted or user-restricted (not document-open) PDFs, or is a scam.

If the PDF has user restrictions (can open but can't print or copy)

This is different from a document-open password. User restriction passwords are much weaker by design, and tools like Docuvory's Unlock PDF tool can remove them. However, Docuvory's unlock tool only works on restriction passwords, not document-open encryption.

Comparison Table

Method	Encryption Level	Permission Control	Works On	Cost
Docuvory	256-bit AES	Open password only	Any device	Free
Adobe Acrobat Pro	256-bit AES	Open + print/copy permissions	Windows, Mac	$19.99/month
macOS Preview	128-bit AES	Open password only	Mac only	Free (built-in)

Frequently Asked Questions

Can I password-protect a PDF on my phone?

Yes. Docuvory's Protect PDF tool works in any mobile browser — Safari on iPhone, Chrome on Android. No app required.

What's the difference between a PDF open password and a permissions password?

An open password (document password) prevents anyone from opening the file without knowing it. A permissions password (user password) allows opening the file but restricts actions like printing, copying, or editing. Both can be set independently. Docuvory sets an open password. Acrobat Pro can set both.

Can I add a password to a PDF I've already created?

Yes. You don't need to recreate the PDF. Just upload the existing PDF to Docuvory's Protect PDF tool, set a password, and download the protected version. The content is identical to the original.

How do I open a password-protected PDF?

When you open a password-protected PDF in any viewer (Adobe Reader, browser, Preview), you'll be prompted to enter the password. Once entered correctly, the document opens normally. The password is required every time the file is opened.

Can I remove the password later?

Yes. If you know the password, use Docuvory's Unlock PDF tool to remove it. Upload the protected PDF, enter the password, and download the unlocked version.

Is my PDF safe when uploading to Docuvory?

All file transfers are encrypted with 256-bit SSL. Uploaded files are processed and then permanently deleted within 1 hour. We never store or access document content. No account or registration is required.

Related Tools

Protect PDF — add a password to any PDF
Unlock PDF — remove an existing password
Sign PDF — add an electronic signature
Watermark PDF — stamp CONFIDENTIAL or DRAFT

How to Password Protect a PDF for Free (3 Methods)