🔒 Lock PDF (Add Password)
Encrypt your PDF with a password — 100% Free, Fast & Secure.
🔒 How to Lock a PDF (Add Password)
Follow these steps to encrypt your PDF securely:
1️⃣ Upload your PDF
Select the file you want to protect.
2️⃣ Enter password(s)
Enter a User Password to open PDF. Optionally enter Owner Password to control editing, printing, copying.
3️⃣ Click “Lock PDF”
Your encrypted PDF downloads instantly.
4️⃣ Enjoy a fully secure PDF
No one can open or modify it without your password.
All Tools
🔐 Free Lock PDF Tool Online — Add Password to PDF in Seconds
Last month my friend sent his salary slip PDF in a WhatsApp group by mistake — whole office saw it. Never again. That’s why I built the free lock PDF tool on Tool100plus.com – add a strong password to any PDF in seconds, no software, no watermark, no limits.
Why You Need to Password Protect PDF Right Now
Our online PDF password protector does exactly what Adobe charges ₹1500/month for:
- Add open password (nobody can open without it)
- Add permission password (open allowed but no print/edit/copy)
- 256-bit AES encryption (bank-level protection)
- Works on invoices, marksheets, salary slips, contracts, ebooks
- Zero files saved — everything processed securely
Students, HR teams, CAs, office workers — everyone uses it daily.
What You Can Secure with This Free PDF Locker
- Add password to PDF (open-password only)
- Full PDF encryption with strong security
- Protect PDF from editing/printing
- Encrypt salary slip or marksheet PDFs
- Secure personal documents (PAN, Aadhaar, property papers)
- Lock multiple PDFs at once — drag & drop 10 files
How to Lock a PDF in 10 Seconds
- Go to tool100plus.com/lock-pdf
- Drag & drop your PDF
- Type your password twice
- Select:
- Open password only OR
- Full protection (no print/edit/copy)
- Click “Lock PDF”
- Download your secured file
I locked my PAN card PDF while standing in the metro — works perfectly on mobile.
Real Stories Where This Tool Saved People
- HR locked 47 offer letters before sending
- Teacher protected question paper PDFs from leaking
- CA secured confidential tax files
- Girl locked her love letters PDF (yes, really)
- Uncle protected property documents from relatives
- Job seeker locked resume before sending to shady consultancies
Why Tool100plus.com PDF Locker Is Actually Trustworthy
- Unlimited files & size (500MB PDFs also supported)
- No watermark, no signup, no ads
- 256-bit AES encryption — practically unbreakable
- Files deleted from server automatically in 30 minutes
- Works on scanned PDFs too
- Batch locking for multiple documents
- Zero data stored — total privacy
Most free tools add their logo, use weak encryption, or secretly collect your files. This one doesn’t.
Stop sending unprotected PDFs like it’s 2010. Lock your PDF now and keep your sensitive info safe.
❓ Frequently Asked Questions
Locking means adding a password so no one can open or edit your PDF without permission.
Yes. Files are auto-deleted after processing and never stored permanently.
Yes—you can allow or block printing, copying, or form editing.
No. Everything works online from your browser.
Yes, using our PDF Unlock tool.