Protect confidential documents before sending them by email: nobody can open the PDF without the password. Helpdf uses AES-256 encryption, the same standard as banks, and your password is never sent anywhere.
How to password protect a PDF
Select your file
Click the button or drag and drop your file into the box.
Choose your options
Adjust the settings if needed — the defaults work for most files.
Download the result
Your new file is created instantly in your browser. Click Download.
Frequently asked questions
What if I forget the password?
The password cannot be recovered: that is what makes the protection secure. Keep it in a safe place.
Are my files safe?
Yes. With Helpdf, your files stay on your device. They are never sent to our servers, nobody else can see them and nothing is stored.
Is Helpdf free?
Yes, every tool is completely free with no sign-up and no watermark. The site is funded by advertising.
Does it work on phone?
Yes. Helpdf works in any modern browser on Android, iPhone, iPad, Windows, Mac and Linux. Very large files may be slower on older phones.