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Protect PDF with a Password Online Free

Lock a PDF with a password using AES-256 encryption. Only people with the password can open it.

Free, no sign-upFiles stay on your deviceNo watermark
Drop a PDF here Select PDF file Add a password with strong AES-256 encryption.

How to password protect a PDF

  1. Choose the PDF

    Select or drop your file.

  2. Set a password

    Type it twice. Optionally restrict printing, copying or editing.

  3. Protect

    Press Protect PDF and download the locked file.

Everyday uses

  • Salary slips and statements – share by email safely.
  • ID documents – protect Aadhaar or PAN copies you email.
  • Client files – send contracts and reports securely.
  • Medical reports – keep health records private.

Good to know

The PDF is encrypted with AES-256, the strongest standard PDF encryption, supported by Adobe Reader, Chrome, Edge, Android and iPhone viewers. The password never leaves your device.

Send the password separately from the file (for example by SMS or a call), not in the same email.

Private by design. Protect PDF works inside your browser. Your file is processed on your device and is not uploaded to our server.

Choosing a password that protects

  • Use at least 10 characters – a short phrase of three or four unrelated words is long and easy to remember.
  • Avoid names, dates of birth, mobile numbers and account numbers: they are the first things anyone tries.
  • Use a different password for each file you send to different people.
  • Keep an unprotected copy for yourself – a forgotten password cannot be reset.

Sending a protected PDF

Send the file and the password through different channels – the PDF by email, the password by SMS or a phone call – so that someone who sees one does not get both.

The open password is what keeps the content private. The print, copy and edit permissions only ask the reader app to block those actions; well-behaved apps respect them, but they are not encryption on their own.

Limits to know before you start

  • A forgotten password cannot be recovered by anyone, including us. Keep an unprotected original somewhere safe.
  • Print and copy restrictions depend on the reader app respecting them; the open password is what really protects the file.
  • Some very old PDF readers cannot open AES-256 files. All current readers can.

If something goes wrong

“The two passwords don’t match”. Type the same password in both boxes.

The file still opens without a password. Check that you opened the new -protected file, not your original.

Protect PDF – questions

How do I put a password on a PDF?

Select the PDF, type a password twice and press Protect PDF.

What if I forget the password?

It can’t be recovered — that’s the point of strong encryption. Keep an unprotected original somewhere safe.

Can I stop people printing or copying?

Yes. Untick the permissions you want to block. Note that these restrictions depend on the reader app respecting them.

Which apps can open a PDF protected here?

Adobe Acrobat Reader, the PDF viewers in Chrome and Edge, Apple Preview on the Mac and the viewers built into iPhone and most Android phones open AES-256 protected PDFs after you type the password. Only very old PDF readers cannot.

This page describes Protect PDF as it works today. If you notice a difference, tell us and we will correct it. See our editorial standards.

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