Add Password to PDF Online Free
Add cryptographically secure AES-256 password protection to your PDF files. Prevent unauthorized reading, copying, or printing.
Need the opposite? Unlock PDF — remove a password from a PDF instead.
Select PDF file to encrypt
Tap anywhere or browse filesor drag and drop it here securely
Facing issues or have suggestions? Report a bug or submit feedback 🐛
Why Pay for Protect PDF? SolveMyPDF vs. Paid Alternatives
Traditional PDF websites charge expensive monthly subscriptions and force you to upload confidential legal, financial, and personal documents to their cloud servers. See how SolveMyPDF compares:
| Feature / Plan | SolveMyPDF 100% Free & Local | Adobe Acrobat |
|---|---|---|
| Monthly Subscription Price | 100% Free Forever ($0) | $19.99 / month ($240/yr) |
| Daily Usage & File Limits | Unlimited (No daily caps) | 1 free trial operation |
| Document Privacy & Security | 100% Client-Side (Zero Server Uploads) | Uploaded to Adobe Cloud |
| Account Signup Required? | No Account or Email Needed | Adobe ID sign-in mandatory |
| File Size Upload Limits | Unlimited (Processed in device RAM) | Strict 100 MB limit |
| Processing Speed & Latency | Instant (Local WebAssembly engine) | Cloud rendering delay |
| Watermarks or Hidden Paywalls | Zero Watermarks, 100% Free | Paywalled after 1 file |
Zero Cloud Uploads
Files are converted inside browser memory using WebAssembly. GDPR & HIPAA safe by default.
Instant Local Execution
No uploading megabytes of data to remote servers or waiting in shared cloud queue lines.
Zero Paywalls & Limits
Never interrupted by daily operation limits, credit card demands, or forced trial subscriptions.
How to Password Protect a PDF in 3 Easy Steps
Select Your PDF
Upload the confidential document you want to secure from your device.
Set Password & Permissions
Type a strong password and choose whether to allow or block printing and text copying.
Download Secured File
Click Encrypt and download your password-locked PDF with permanent cryptographic safety.
Frequently Asked Questions
What happens if I forget the password?
Because encryption uses standard AES cryptographic keys with zero backdoors, it is impossible to recover a document without the correct password. Please keep your password safe.
Is client-side encryption reliable?
Yes. The encryption engine writes standard ISO-32000 crypt dictionaries natively, making it 100% compatible with Adobe Acrobat and enterprise security scanners.
Can I lock both opening and printing?
Yes. You can require a password to view the PDF, or restrict modifications and printing independently.
Is there any cost or limit?
Protecting PDFs on SolveMyPDF is completely free and unlimited for personal and business use.