Protect PDF
Add a password to keep a PDF private.
Add a password to keep a PDF private.
How to use Protect PDF
- Upload the PDF you want to lock
- Set a strong open password with AES-256 encryption
- Optionally restrict printing, copying, and editing
- Download the protected file, processed locally
About Protect PDF
Protect PDF password-protects any PDF so only people who know the password can open it — and it does the whole job in your browser, with no Adobe Acrobat, no desktop software, and no account. Choose a file, type the password you want to require, and the tool encrypts the PDF with AES-256, the same strength standard used for banking and government documents. The protected copy downloads straight back to you.
There are two kinds of password you can set. The open (user) password is the one required just to view the file. The optional owner password lets you keep a PDF readable while restricting printing, copying text, and editing — useful when you want to share a document to be read but not reused or altered. You can set one or both.
Encryption has no back door, so if you forget the open password the PDF can't be opened — store it somewhere safe — and to remove protection later, just open the file with its password in any viewer. It's free and unlimited, with no watermark and no sign-up. Best of all, the file and password are encrypted right on your device and never uploaded, so protecting a PDF stays private whether you're on Windows, a Mac, a Chromebook, or a phone — anywhere a browser runs.
Frequently asked questions
- How do I password protect a PDF?
- Open the tool, choose your PDF, and enter the password you want to require to open it. The file is encrypted with AES-256 in your browser and the protected copy downloads right back to you — there's no Acrobat, software install, or account needed.
- Can I password protect a PDF without Adobe Acrobat?
- Yes. Adobe Acrobat's password feature needs a paid subscription, but this tool encrypts your PDF for free in the browser. It applies the same standard PDF encryption, so the file opens normally in Acrobat Reader, Preview, or any other viewer once the password is entered.
- Can I stop people from printing, copying, or editing my PDF?
- Yes. Alongside the password to open the file, you can set an owner password that restricts printing, copying text, and editing. That lets you share a PDF people can read but not reuse or alter.
- What's the difference between the open password and the owner password?
- The open password is required to view the PDF at all. The optional owner password lets you also set permissions — for example allowing viewing but blocking printing or copying — while keeping the ability to change those settings.
- How strong is the protection?
- It uses AES-256 encryption — the strongest standard PDF encryption, the same class used by banks and governments.
- Does this work on Windows, Mac, and phones?
- Yes. It runs entirely in your web browser, so it works the same on Windows, macOS, Chromebook, iPhone, and Android. There's nothing to install and no app to download — you just need a modern browser.
- Is my PDF or password uploaded to a server?
- No. The PDF is encrypted entirely in your browser using your device's built-in cryptography, so neither the file nor the password ever leaves your device.
- Is Protect PDF free?
- Yes — completely free with no sign-up, no watermark, and no limits.
- Will it add a watermark or limit the file size?
- No. There's no watermark on the protected PDF and no sign-up, and there's no cap on how many files you protect. Because processing happens on your own device, larger files depend on your device's memory rather than an upload limit.
- Can I recover the password if I forget it?
- No. There is no back door — if the password is lost, the PDF can't be opened. Store it somewhere safe.
- Can I remove the password later?
- Yes, as long as you know it: open the PDF with the password in any viewer. Note that our Unlock PDF tool only removes owner-permission restrictions, not a password required just to open the file.