Is Protect PDF free to use?

Yes. Protect PDF is free in your browser with no sign-up. Free plan supports files up to 50 MB with fair-use limits. AstraPDF Plus removes caps and ads.

What if I forget the password?

Passwords cannot be recovered. Store your password securely. Use Unlock PDF only if you know the password.

Can I use this on mobile?

Yes. Open the tool in Safari, Chrome, or Firefox on any smartphone or tablet — no app required.

Do I need a paid account?

No. Protect PDF works on the free plan. Plus is optional for unlimited processing and larger files.

Protect PDF with Password - Free PDF Password Protection Tool

Q: Is it safe to use Protect PDF online?

Yes. AstraPDF processes files on your device. Your files are processed locally in your browser — nothing is uploaded to our servers. We cannot access your documents.

Choose PDF File

or drop a PDF file here

Select File

PDF only · One file at a time

Password encryption

Set an open password so only authorized readers can view the document.

Keep files confidential

Ideal for contracts, financial records, and personal documents.

Secure — files never uploaded

Your files are processed locally in your browser — nothing is uploaded to our servers.

How to password-protect a PDF

Encrypt your PDF in four steps.

1
Upload your PDF
Select the file to protect.
2
Set a password
Choose a strong password — store it safely, it cannot be recovered if lost.
3
Encrypt
Apply password protection in your browser.
4
Download
Save your encrypted PDF.

Everything you need to protect PDFs

Add password security without sending files to the cloud.

Start immediately — no fuss

Use Protect PDF directly in your browser. No sign-up, no software install.

Works on any device

Desktop, tablet, or phone on Windows, Mac, Linux, iOS, and Android.

No watermarks on output

Download clean results on Free and Plus — no branding stamped on your files.

100% browser-based privacy

Your files are processed locally in your browser — nothing is uploaded to our servers.

Combine with other PDF tools

Chain tools together — merge, compress, convert, protect, and sign in one workflow.

Optional Premium upgrade

AstraPDF Plus removes file-size caps, fair-use limits, and ads — still 100% private in your browser.

When to password-protect a PDF

Contracts & legal

Encrypt agreements before email.

Financial records

Protect tax docs and statements.

After merging

Lock a combined confidential file.

Personal documents

Secure IDs, medical records, and private files.

Protect PDF FAQs

Common questions about protect pdf with AstraPDF.

Need more power?

Protect unlimited PDFs

AstraPDF Plus removes file-size caps, fair-use limits, and ads — still 100% private in your browser.

Get Premium

Related PDF tools

Unlock PDF

Remove passwords

Merge PDF

Merge protected files

E-Signature

Sign protected PDFs

Compress PDF

Compress before protecting

Need more power? See our pricing plans or browse all tools on the homepage.

Protect PDF with Password — Free Online