Protect PDF – Add a Password
Lock your PDF with a password and strong AES-256 encryption — free and online.
Upload a PDF to Protect
Drag & drop your file here, or click to browse
Choose PDF FileHow to Password Protect a PDF in 3 Easy Steps
Keep private documents safe before you email, upload or share them.
Upload Your PDF
Drag and drop your PDF into the box above, or click Choose PDF File. Files up to 50 MB are supported.
Choose a Password
Type your password twice. If you like, untick printing, copying or editing to block them.
Download the Protected PDF
Click Protect PDF, then Download. Anyone opening the file must now enter your password.
Why Protect Your PDF with Toolszu
Strong encryption that works in every PDF reader.
AES-256 Encryption
The strongest encryption used in PDF files. Without the password, the content can't be read.
Control What People Can Do
Choose whether people who open the PDF can print it, copy from it or edit it.
Works in Every Reader
Opens in Adobe Acrobat, Chrome, Edge, Safari, macOS Preview and phone PDF apps — after entering the password.
We Never Store Passwords
Your password is only used to encrypt this one file and is never saved or logged.
Private and Secure
Encrypted upload, isolated processing and automatic deletion within 1 hour.
Free, No Watermark
No sign-up and no Toolszu logo in your PDF.
When to Password Protect a PDF
Add a password before sharing anything personal or confidential.
Financial Documents
Salary slips, invoices, tax returns and bank statements.
ID and Personal Papers
Copies of ID cards, passports, certificates and medical reports.
Contracts & Agreements
Share drafts with clients without others reading them.
Business Reports
Internal reports, price lists and plans you send by email.
Exam & Study Material
Question papers and notes for a closed group.
Email Attachments
Send the password separately (for example by SMS) for extra safety.
Tips for a Strong PDF Password
- Use at least 8–12 characters with a mix of letters, numbers and symbols. Avoid names and birthdays.
- Remember your password! Nobody — including Toolszu — can recover it for you, because it is never stored.
- Share the password separately from the file, for example by phone or message.
- Need to remove it later? Use Unlock PDF with the same password.
Frequently Asked Questions
Quick answers about adding a password to PDF files.
Upload your PDF, type a password twice and click Protect PDF. Download the new file — it now asks for the password when opened. It's free, with no sign-up.
Your PDF is encrypted with AES-256, the strongest encryption available in the PDF standard. Without the password, the content can't be read.
We can't recover it, because your password is never stored. Keep a copy of the original unprotected file, or write the password down somewhere safe.
Yes. Untick Print, Copy or Edit before protecting. Most PDF readers follow these settings after the password is entered.
Yes. Any modern PDF reader can open it after the password is entered — Adobe Acrobat, Chrome, Edge, Safari, macOS Preview and mobile PDF apps.
Remove the old password first with Unlock PDF, then protect it with your new password.
No. It's only used to encrypt your file and is never stored or logged. The file itself is deleted within 1 hour.
You can upload PDFs up to 50 MB and 500 pages, and convert up to 20 PDFs per day for free. The daily limit resets every day.
Yes. Open this page in Safari, Chrome or any mobile browser, choose your file and tap the button. No app is needed.
Yes. Your file is sent over an encrypted connection, converted in an isolated sandbox with no internet access, never shared with anyone and deleted automatically within 1 hour. You can also delete it right away with the Delete now button.
Yes, it's 100% free. There's no sign-up, no premium version and no watermark or Toolszu logo added to your file.
Related Free PDF Tools
Unlock PDF
Remove a PDF password
Compress PDF
Reduce PDF file size online
Sign PDF Online
Add your signature to a PDF
Watermark PDF
Add a text or logo watermark
Edit PDF Online
Change PDF text in the same font
Merge PDF
Combine multiple PDFs into one
Split PDF
Extract pages or split a PDF
PDF to Word
Convert PDF to an editable Word file
Repair PDF
Fix damaged or corrupted PDFs
Ready to Lock Your PDF?
Add a password with AES-256 encryption in seconds — free, with no sign-up.
Protect PDF Now