Lock PDF Online
Protect your PDF with a password in seconds. Keep sensitive documents private and share them only with the people you choose. No software to install, no watermarks.
Lock PDF is locked
Lock PDF is not available for guest users. Please sign in to unlock it.
As a guest you get 5 conversions per day, 1 file per task and up to 20 images per Image to PDF task.
How it works?
Upload your file
Drag and drop your .pdf file, or browse from your device.
Set a password
Type the password you want to use to open the file.
Download your protected PDF
Save the locked file, share it, or store it safely.
Why choose our Lock PDF tool?
Password protection
Only people with the password can open your PDF.
Content stays untouched
Text, images, and layout remain exactly as they were.
100% free
No hidden fees, no watermarks, no account needed.
Fast results
Most files are locked in just a few seconds.
Works everywhere
Windows, Mac, Android, iPhone, or Linux. Any browser works.
Secure by design
Files are processed securely and deleted automatically.
Nothing to install
No Adobe Acrobat or desktop software needed.
Why lock a PDF?
Documents like contracts, bank statements, resumes, and ID copies often contain private information. Sending them without protection means anyone who gets the file can read it. Adding a password makes sure only the intended person can open it, which adds a simple layer of security when you email, upload, or store important files.
Protect a PDF with a password
Sending a contract, ID scan, or financial statement? Add a password with the Protect PDF tool so only people who know it can open the file.
Set a password, download the locked copy, and share the password through a separate channel for better security.
Quick tips
- Use a long password that mixes words, numbers, and symbols.
- Send the password by a different route than the file.
- Store the password somewhere safe because it cannot be recovered from the file.
How to password protect a PDF before you share it
How do I put a password on a PDF for free?
Upload your PDF, type the password you want, confirm it and download the protected copy. Anyone who opens the new file must enter that password first. Your text, images and layout are not changed.
The tool shows a strength meter and a checklist while you type: at least eight characters, an upper-case letter, a lower-case letter, a number and a symbol. Following it gives you a much stronger password than a single word or a date.
How do I send a protected PDF by email safely?
Protecting the file is only half of the job. Do not put the password in the same email as the attachment. Send it through another channel, such as a text message or a phone call, so that someone who sees only the email cannot open the document.
What does a PDF password actually protect?
A password controls who can open the file. It does not stop a person who has the password from saving, copying or forwarding the contents afterwards, so share the password only with people you trust to see the document.
The tool applies the same password for opening and for the file owner, and it does not add printing or copying restrictions on top. If the PDF is already password protected, unlock it first and then set a new password.
What should I do if I forget the password?
Passwords cannot be recovered or reset from the file. Keep an unprotected original in a safe place, and store the password in a password manager so you are never locked out of your own document.
Popular ways to use it
Email a contract or ID copy
Protect the attachment so only the intended person can open it.
Share bank or tax statements
Add a password to financial documents before you send them to an accountant.
Send a resume with personal details
Protect a CV that includes your address, phone number or ID details.
Store private documents
Keep medical, legal or insurance files protected in cloud storage or on a shared drive.
Protect client reports
Add a password to confidential reports and proposals before they leave your company.
Troubleshooting and common problems
It says the PDF is already password protected.
Unlock the file first with the Unlock PDF tool and its current password, then lock it again with the new password.
The passwords do not match.
Retype both fields carefully. You can show the characters with the eye icon to check what you typed.
The recipient cannot open the file.
Check that they are typing the exact password, including capital letters and symbols, and that you did not add spaces when sending it.
My protected file will not merge or edit.
Other tools cannot work on a locked PDF. Edit or merge the unprotected version first, and add the password as the last step.
Good to know
- Opening password
- Anyone who opens the file must enter the password you chose.
- Content is untouched
- Only password protection is added. Pages, text and images stay exactly the same.
- No recovery
- The password cannot be reset from the file, so keep it somewhere safe.
- Lock last
- Finish merging, editing and signing first, because locked files cannot be changed by other tools.
Who uses this tool?
Students
Protect personal records, transcripts, and submissions.
Job seekers
Secure resumes and ID documents before sharing them online.
Professionals
Keep contracts, reports, and client files confidential.
Business owners
Protect invoices, financial statements, and internal documents.
FAQs
Is this Lock PDF tool really free?
Yes. It's free to use, with no watermark and no signup.
Will locking change my PDF content?
No. Only password protection is added. Text, images, and layout stay exactly the same.
What happens if I forget the password?
We can't recover or reset passwords, so keep it somewhere safe. Without the password, the file can't be opened.
How strong is the encryption?
Your PDF is protected with 256-bit AES encryption.
Can I lock a PDF on my phone?
Yes. It works on smartphones, tablets, and computers.
Are my files safe?
Yes. Files are handled securely and removed from our servers after processing.
Is there a file size limit?
Files up to 50 MB are supported.
How do I put a password on a PDF?
Upload the PDF, type your password, and download the protected file.
What if I forget the password?
It cannot be recovered from the file, so keep an unprotected original somewhere safe.
How do I encrypt a PDF before emailing it?
Add a password with the Protect PDF tool, attach the protected copy to your email, and send the password separately.
What makes a good PDF password?
Use a long mix of upper-case and lower-case letters, numbers and symbols that is not a name or date. A password manager can create and store one for you.
Can I protect a PDF with a password on my phone?
Yes. The steps are the same on a phone or tablet: upload, set the password, download.
Is a password-protected PDF safe from being copied?
The password controls who can open it. Someone with the password can still copy or share the content, so only share it with people you trust.
Can I change the password later?
Unlock the file with the current password, then lock the unlocked copy with a new one.