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Protect PDF

Password-protect sensitive PDFs. Apply encryption so only people with the password can open the file.

No document data Download No Sign-up Required

01 / Add a file

Choose the PDF to protect

One document, processed locally in this browser.

Single file · Max 256 MB

Core processing stays in this browser after the page loads. Large files use device memory and may run slower.

Protect PDF

Apply encryption so only people with the password can open the file.

Quick answer

How do I password-protect a PDF for free?

Upload the PDF, set a strong password, then download the encrypted file. Encryption runs locally — your password is not sent to our servers. Store passwords securely; we cannot recover lost passwords.

Privacy by default

Upload the PDF, set a strong password, then download the encrypted file. Encryption runs locally — your password is not sent to our servers. Store passwords securely; we cannot recover lost passwords.

How to protect a PDF

How to protect a PDF

Set password, download

  1. 01

    Upload PDF

    Choose a file.

  2. 02

    Set password

    Enter a strong passphrase.

  3. 03

    Download

    Save the protected PDF.

Lock PDFs before sharing

Lock PDFs before sharing

Browser-based encryption

01

100% in your browser

Files stay on your device. No uploads to our servers — ideal for confidential documents.

02

No account required

Get started instantly. No registration, no credit card, no watermarks on exports.

03

Fast local processing

PDF work runs locally in your browser for quick results — no round-trip to a server.

04

Works everywhere

Use Chrome, Firefox, Safari or Edge on desktop and mobile — no install needed.

05

Privacy by design

We never store your files. Processing happens in memory in your tab.

06

Core tools free

Protect with no account limits — built for everyday document tasks.

Protect PDF FAQ

Protect PDF FAQ

Passwords and recovery

Do you store my password?

No — processing happens in the browser.

AES encryption?

Depends on library support in the tool.

Forgot password?

We cannot crack it — keep a secure backup.

Unlock later?

Use our Unlock PDF tool with the correct password.

Compatible with Adobe?

Standard PDF encryption is widely supported.

Free?

Yes for basic protection.

Learn before you process

PDF guides for this workflow

Get the answer, understand the trade-offs, then use the focused tool when you are ready.

How to password-protect a PDF before sharing

Create a protected copy, choose a strong passphrase, and share the file and the password separately.

Read the security guide

Is iLovePDF safe for confidential documents?

What iLovePDF and Smallpdf say about encryption, retention and access, what that does not cover, and how to decide whether a confidential PDF should be uploaded.

Read the safety guide

How to watermark a PDF (text, image or a PDF overlay)

Stamp text or an image on every page, or lay one PDF over another, and understand what a watermark does and does not protect.

Read the watermark guide

Comparing PDF tools? FreePDFKit vs iLovePDF · FreePDFKit vs Smallpdf · Browser-local vs cloud PDF tools

Related PDF tools

Verify it yourself

Your file is not uploaded. Here is how to check.

The core tools run inside your browser tab, so a document you open here is not sent to FreePDFKit or to anyone else. You can confirm that in about a minute.

  1. Step 1

    Open the tool and let it load

    Wait until the page has finished loading.

  2. Step 2

    Open your browser’s developer tools

    Press F12 (or Cmd+Option+I on a Mac) and switch to the Network tab.

  3. Step 3

    Run the tool on a test file

    Choose a non-sensitive file of the type the tool accepts and process it as usual.

  4. Step 4

    Look for a request that carries the file

    You will not find one. The page loads its own scripts, then the work happens in your browser.

What backs this up

  • Open-source libraries in the page. PDF handling uses libraries such as pdf-lib and Mozilla’s PDF.js, which run in your browser.
  • No PDF endpoint on the server. The only server routes are the contact form and the social-preview image generator.
  • A restrictive security policy. The site’s Content-Security-Policy limits the fetch and XHR connections page scripts can make to our own origin, Google analytics services and Cloudflare’s anti-spam check.

More detail in the privacy policy and how this compares with other no-upload options.