How to Lock a PDF with a Password
Add password protection to any PDF using 256-bit AES encryption. The same standard used by banks and governments, available for free with no account required.
Server-side processing means your file is transferred securely, encrypted, and permanently deleted the moment your download is ready. Your password is never stored or seen by anyone.
Lock Your PDF in 3 Steps
Upload Your PDF
Drag your file onto the upload area or click to browse. Files up to 50MB are supported. If your PDF is already password protected, you will need to unlock it first.
Choose a Password
Type a password in the Set Password field. A live strength meter shows whether your password is Too Short, Weak, Fair, Good, or Strong as you type. Re-enter it in the Confirm Password field. A green match indicator appears when both fields are identical. The minimum length is 4 characters, but a strong password uses 8 or more characters with a mix of letters, numbers, and symbols.
Download Your Locked PDF
Click Lock PDF. A progress panel shows each stage in real time: uploading, applying encryption, and preparing the download. When it reaches 100% you will see "Encryption Complete!" Click Download Locked PDF to save your file. Click Start Fresh to lock another document.
What Makes This PDF Lock Tool Worth Using
Fast, secure, and honest about what happens to your file.
256-bit AES Encryption
The same encryption standard used by banks, governments, and security professionals. Your PDF is fully protected the moment it is locked.
Live Password Strength Meter
As you type, a colour-coded bar tells you whether your password is Too Short, Weak, Fair, Good, or Strong. A green indicator confirms both fields match before you proceed.
Password Never Stored
Your password is used to lock the file and immediately discarded. We never log it, store it, or have any way to retrieve it later.
Real-Time Progress Tracking
A step-by-step panel shows exactly what is happening: uploading, encrypting, and preparing your download. A live percentage bar keeps you updated throughout.
Auto-Deleted After Download
Files are processed in server memory only and permanently deleted the moment your locked PDF is ready. Nothing is written to permanent storage.
Works on Any Device
iPhone, Android, iPad, or desktop. Any modern browser can use this tool without installing any software.
When to Password Protect a PDF
Locking a PDF is a good idea any time you are sharing something sensitive:
- Sending contracts or legal agreements to clients or counterparts.
- Sharing financial statements, tax documents, or payslips.
- Protecting medical records and personal health information.
- Distributing HR documents and confidential employee files.
- Sending personal identification or government documents.
- Adding a layer of protection before uploading to file storage or email.
What Happens to Your File
Your PDF is transferred to our server over an encrypted connection.
It is processed in server memory only. Nothing is written to permanent disk storage.
Your password is applied to the file and then immediately discarded.
The locked PDF is returned to your browser and the server copy is deleted right away.
We never log, store, or have access to your password at any point.