Password Protect PDF
Lock your PDF with a password using AES-256 encryption, right in your browser.
- ✓Files never uploaded
- ✓Free plan, no card needed
- ✓Free account, no card
- ✓No watermark
How to Protect PDF
- 1Drop your PDF into the box or click to choose it.
- 2Enter a password and type it again to confirm.
- 3Click Protect PDF and download the encrypted file.
Why pdfdots?
Private by design
Most tools process files locally in your browser. Office conversions run on our EU server and are deleted right after; anything you save to My files is encrypted.
Generous free plan
A free account with Google sign-in and no credit card: 3 tasks a day, files up to 10 MB, every tool. Need more? The paid plans (Bronze, Silver and Gold) raise the daily limit, with no daily limit at all on Silver and Gold, and accept larger files.
Fast
For browser tools there's no upload or download queue. Work starts the moment you drop a file and finishes at the speed of your own computer.
Works everywhere
Windows, Mac, Linux, iPhone, Android or Chromebook — if it has a modern browser, pdfdots runs on it. Nothing to install.
Keep sensitive PDFs private with a password
Bank statements, contracts, medical records and HR documents often travel by email or sit in shared folders where the wrong person could open them. Adding a password means anyone who opens the PDF must enter it first. This tool encrypts the file with AES-256, the strongest encryption the PDF format supports and the same standard used by banks and governments.
The encryption is done by qpdf, a well-established open-source PDF library, running directly in your browser through WebAssembly. That means the unprotected file is never uploaded to a server — not ours, not anyone's. The encrypted PDF opens normally in Adobe Acrobat, Preview, Chrome, Edge and other modern readers once the password is entered.
Choose a strong password: long, unique and not easy to guess, ideally a passphrase of several words. Share it through a different channel than the file itself, for example send the PDF by email and the password by text message. Keep it somewhere safe, because we never see or store your password and cannot recover it if you forget it. If you lose it, the only option is to protect the original file again with a new one.
Our take
We add a password before sending documents through channels we do not fully control: payslips shared with an accountant by email, a medical report uploaded to a shared drive, or tax papers on a USB stick.
We choose a long passphrase rather than a short complex password, and we send it through a different channel than the file, for example by phone or text message. Sending the password in the same email defeats the purpose.
The pitfall we see is forgetting the password; there is no recovery, and that is the point of encryption. Keep it in a password manager. If you only want to signal that a file is confidential rather than lock it, Add Watermark is the lighter tool, and for removing a known password later, use Unlock PDF.
Related tools
Free fillable PDF templates
Guides & comparisons
- How to Password Protect a PDF the Right Way
- Are Online PDF Tools Safe? A Practical Guide to Protecting Your Documents
- A free alternative to Adobe Acrobat online
- Soda PDF alternative: the everyday tools, simpler
- PDFescape alternative: edit, fill and sign PDFs in your browser
- pdfdots as a PDFgen alternative
Frequently asked questions
How strong is the encryption?+
The PDF is encrypted with AES-256, the strongest standard encryption available for PDF files.
Is my file uploaded to protect it?+
No. Encryption runs locally in your browser with qpdf compiled to WebAssembly.
What if I forget the password?+
We can't recover it, because we never see or store it. Keep your password somewhere safe.
Will the protected PDF open everywhere?+
Yes. Modern readers like Acrobat, Preview, Chrome and Edge open it after the password is entered.
Can I remove the password later?+
Yes. Use our Unlock PDF tool and enter the current password.
Is it free?+
Yes. You only need a free account (sign in with Google, no credit card), with no watermark. The free plan includes 3 tasks a day; Silver and Gold have no daily limit.