Lock / Unlock PDF
Add or remove password protection from your PDF documents.
Drop your PDF here
or
Maximum file size: 20MB
Locking a PDF
- Choose the Lock PDF tab.
- Upload the PDF you want to protect.
- Enter the password you want to set; it must be at least four characters.
- Download the protected file and confirm the password works before deleting your original.
Unlocking a PDF
- Choose the Unlock PDF tab.
- Upload the protected PDF.
- Enter the current password.
- Download the unlocked copy.
What the Password Actually Restricts
When you lock a file here, the resulting PDF requires the password to open and is set to allow printing while restricting editing, copying and annotation.
It is worth understanding that PDF permissions are enforced by the reader application, not by the file itself. A compliant reader will honour them; permissions are a deterrent against casual copying rather than a hard security guarantee. The open password is the part that genuinely protects the contents.
A Forgotten Password Cannot Be Recovered
Unlocking requires the correct existing password, because the file has to be decrypted before it can be rewritten. If you no longer know it, this tool cannot help, and neither can any tool that claims to remove protection without it.
If you supply an incorrect password the request fails with a clear message. The practical route in that situation is to obtain an unprotected copy from whoever created the document.
Limits
- One PDF per operation.
- Passwords may be up to 128 characters; locking requires at least four.
- The document may contain up to 300 pages.
- A PDF that is already protected cannot be locked again; unlock it first.
- Requests are rate limited to ten per minute from the same address.
Common Use Cases
- Protecting a statement, payslip or medical report before emailing it.
- Adding a password to a document shared over chat.
- Removing a password from a file you own so you can merge or edit it.
- Preparing a document that a recipient needs to open without a password.
Privacy and Processing
Both operations run on our server, so the file and the password you type are transmitted to it in order to process the request. The file is used only for that operation and the download is removed after it is sent. For highly sensitive material, consider desktop software that never leaves your machine.
Lock / Unlock PDF FAQ
Can you remove a password I have forgotten?
No. Unlocking requires the correct existing password because the file must be decrypted before it can be rewritten. No legitimate tool can bypass this. If you no longer know the password, ask whoever created the document for an unprotected copy.
What does the password actually restrict?
The protected file requires the password to open, and is set to allow printing while restricting editing, copying and annotation.
How secure is PDF password protection?
The open password genuinely protects the contents. The permission settings, however, are enforced by the reader application rather than by the file itself, so they deter casual copying rather than providing a hard guarantee.
What are the password requirements?
A password you set must be at least four characters and may be up to 128. When unlocking, you simply enter the existing password.
Can I lock a PDF that is already protected?
No. Unlock it first, then apply the new password.
Is my password sent to the server?
Yes. Both operations run on our server, so the file and the password are transmitted in order to process the request. The file is used only for that operation and the download is removed after it is sent. For highly sensitive material, consider desktop software instead.
Related Developer Tools
Keep moving through common developer workflows with Merge PDF, Compress PDF, Split PDF. You can also browse the full Developer Tools collection or return to the all tools hub.