How do I add a password to a PDF for free?

Upload your PDF to PDFJolt, enter a password and confirm it, then click Lock PDF. The encryption happens entirely in your browser — your file and password are never uploaded to any server. Download the protected PDF and share it securely.

Is the password-protected PDF secure?

PDFJolt uses AES-256 encryption (PDF 2.0 standard), the strongest encryption available for PDF files — the same standard used by governments and financial institutions. It's supported by all major PDF readers including Adobe Acrobat, Preview, Chrome, and Firefox. For maximum security, use a strong password with a mix of uppercase, lowercase, numbers, and symbols.

Can I remove the password later?

Yes. Use PDFJolt's Unlock PDF tool to remove the password. You'll need to know the password to decrypt the file. Go to the "Unlock PDF" tool, upload your locked PDF, enter the password, and download the unprotected version.

Are my files uploaded when I lock a PDF?

No. PDFJolt processes everything in your browser using WebAssembly. Your PDF and password never leave your device — not even temporarily. The encryption happens locally on your computer.

What happens if I forget the password?

PDFJolt does not store your password anywhere — it's used only in your browser's memory during encryption. If you forget the password, there is no way to recover it. Make sure to save your password in a secure location like a password manager.

Lock PDF Online Free

How to Lock PDF Online

1

Upload your PDF by dragging it into the drop zone or clicking to browse (up to 50 MB).

2

Enter a strong password and confirm it. The strength indicator shows how secure your password is.

3

Optionally expand 'Permissions' to restrict printing, copying, editing, annotating, or form filling.

4

Click 'Lock PDF' to encrypt with AES-256 encryption entirely in your browser.

5

Download your password-protected PDF — it's ready to share securely.

Lock PDF — Frequently Asked Questions

About Lock PDF

Why Password-Protect PDF Files?

PDF files often contain sensitive information — contracts, financial statements, medical records, legal documents, personal identification. When sharing these files via email, cloud storage, or messaging apps, adding password protection ensures that only authorized recipients can open and read the content.

According to IBM (2024), the global average cost of a data breach is $4.88 million, rising to $10.22 million in the United States. Fortune Business Insights (2024) values the global data protection market at $150.38 billion — password-protecting sensitive PDFs is a critical first line of defense.

Common scenarios where you need to lock a PDF:

Sharing contracts: Protect confidential agreements sent to clients or partners.
Financial documents: Secure tax returns, invoices, or bank statements before emailing.
Medical records: Add a layer of security to health documents shared with providers.
Legal filings: Protect sensitive legal documents during electronic transmission.
Employee records: Secure HR documents like offer letters, reviews, or payroll information.

How PDFJolt Locks PDFs Differently

Most online PDF encryption tools require you to upload your file to their servers. That means your sensitive document — the one you're trying to protect — travels across the internet to a stranger's server before being encrypted. PDFJolt takes a fundamentally different approach:

No upload required. Your file is encrypted entirely in your browser using WebAssembly.
Password stays local. Your password is used only in your browser's memory and is never transmitted.
Works offline. Once the page loads, you can lock PDFs without an internet connection.
Instant processing. No upload/download time — encryption happens in milliseconds.

PDFJolt vs Other PDF Encryption Tools

Feature	PDFJolt	iLovePDF	Smallpdf	Adobe Acrobat
Price	Free (2/day)	$7/mo	$9/mo	$19.99/mo
Encryption	AES-256 (strongest)	AES-128	AES-128	AES-256
Permissions control	Yes (5 options)	Limited	No	Yes
Privacy	Client-side (no upload)	Cloud upload	Cloud upload	Cloud upload
Max file size	50 MB	25 MB (free)	5 MB (free)	Unlimited
Works offline	Yes	No	No	Desktop only
Account required	No	No	No	Yes

Technical Details

PDFJolt uses AES-256 encryption (PDF 2.0 / V5 R5), the strongest encryption standard available for PDF files. This is the same encryption standard used by governments, banks, and healthcare organizations to protect classified and sensitive information. It is compatible with all major PDF readers:

Adobe Acrobat Reader
macOS Preview
Google Chrome built-in viewer
Firefox built-in viewer
Microsoft Edge
Foxit Reader

Permissions Control

Beyond password protection, PDFJolt lets you control what recipients can do with your PDF. You can restrict:

Printing: Prevent the document from being printed.
Copying: Block text and image selection and copying.
Editing: Prevent content modifications (restricted by default).
Annotating: Disable comments and markup.
Form filling: Prevent interactive form fields from being filled.

These permissions are enforced by compliant PDF readers like Adobe Acrobat. The entire encryption and permissions process happens in your browser — no data is transmitted to any server at any point.

Lock PDF