Lock PDF
Password protect a PDF online for free with AES-256. No sign-up, no watermark — only people with the password can open it.
Select a file or drop it here
.pdf · up to 25 MB
document.pdf
0 KB
0 images · one per page
Locking…
This usually takes a few seconds.
Select or drop your PDF file
Choose the password to protect it
Download your locked PDF
Need to remove a password instead? Unlock PDF
To password protect a PDF for free, upload it above, choose a password, and download the locked file in seconds. It is encrypted with AES-256, so anyone opening it will need that password. Keep the password safe — a locked PDF cannot be recovered without it. No sign-up, no email, and no watermark, and files are never stored.
Lock PDF — free online password protection
Need to password protect a PDF before you email or share it? Our free lock PDF tool adds a password to your document in seconds, right in your browser. There is nothing to install, no account to create, and no watermark added to your file. Just upload your PDF, choose a password, and download the protected result.
Password protect a PDF with strong encryption
Our lock PDF tool adds a password to your document using AES-256 encryption — the same modern standard used to protect sensitive files. Once locked, the PDF cannot be opened, read, or printed without the password you set, so you can safely email or share confidential documents like contracts, statements, and reports. Upload your PDF, choose a password, and download a protected copy in seconds.
How to put a password on a PDF
Adding a password takes three steps: upload your PDF, type the password you want in the box, and download the locked file. Everyone you share it with will be asked for that password before the document opens, in any PDF reader on Windows, Mac, iPhone, or Android. Keep the password somewhere safe — for security there is no way to recover a locked PDF if you forget it.
Lock PDF — free, private, no email
This is a genuine password protect PDF free tool. There is no sign-up, no email verification, and no watermark on your file. Your PDF is encrypted on the server and never stored — it is discarded the moment your download is ready. When you need to remove a password from a PDF you can open, use our Unlock PDF tool.
Which PDFs can I lock?
Any normal PDF can be locked, including a scanned or image PDF — the content does not matter, the whole file is encrypted. A PDF that is already password-protected should be unlocked first with our Unlock PDF tool, then locked again with your new password. Large PDFs up to 25 MB are supported; if yours is bigger, compress it first — a smaller file is also easier to share once locked.
Free, private, and on every device
This lock PDF tool has no limits, no watermark, and no catch. Your privacy is built in: your PDF and the password you choose are processed on the server and never written to disk or stored, then discarded the moment your download is ready. It works on any device, from Windows and Mac to iPhone and Android. When you need to take a password back off, our Unlock PDF tool works exactly the same way.
Frequently asked questions
How do I password protect a PDF for free?
Upload your PDF above, type the password you want, and download the locked file. It is encrypted with AES-256, so anyone who opens it will need that password. There is no sign-up, no watermark, and no cost.
What encryption is used to lock the PDF?
We use AES-256, a strong, modern encryption standard supported by all current PDF readers. The password you choose is required to open the document.
What happens if I forget the password?
For security there is no back door — a locked PDF cannot be opened or recovered without its password. Store the password somewhere safe before you share the file.
Are my files kept private when I lock a PDF?
Yes. Your PDF and password are processed on the server and never written to disk or stored. Everything is discarded the moment your download is ready.
How do I lock a PDF on Windows, Mac, iPhone, or Android?
The same way on every device. This is a free online tool that runs in your browser, so there is nothing to install. Open this page on any device, upload your PDF, set a password, and download the locked file.
Will the password be required every time the PDF is opened?
Yes. Once locked, the PDF asks for the password every time it is opened in any PDF reader. Only people you give the password to can view the document.
From the blog
How to Email Sensitive Documents Safely
Payslips, ID scans, contracts, and medical letters travel through more hands than you think. Encrypting the file — and sending the password separately — is the practical baseline.
How to Password Protect a PDF
Add a real password to a PDF with AES-256 encryption in seconds — free, online, no software. Here is how it works and when you actually need it.
Your privacy comes first
Every uploaded file is processed securely over an encrypted connection and is never written to disk or stored — it is automatically discarded the moment your download is ready. We never ask for an email address, and you never need to create an account before you can download your document. Read more in our Privacy Policy.
You may also need
Last updated: July 2026