Add a password to any PDF document in seconds. Set an open password so only authorised people can view it, optionally restrict printing or copying, and download the secured file — everything happens in your browser, nothing is uploaded.
Open PDF Password Tool → free, no sign-inPDF password protection is built into the PDF standard — any compliant reader will enforce it. An open password prevents someone from viewing the document without entering the correct password. A permissions password goes further, restricting what a viewer can do even after they've opened it: printing, copying text, filling in forms, or making edits can all be individually controlled.
Most tools that add passwords to PDFs do so by uploading your file to a remote server. That creates an obvious problem: the moment you upload a confidential document to apply a password, you've already shared it with a third party. This tool uses pdf-lib — a JavaScript PDF library — to apply encryption entirely inside your browser tab. Your document stays on your device throughout.
The secured PDF you download is a standard password-protected PDF that opens in Adobe Acrobat, Apple Preview, Chrome, Firefox, and any other compliant reader. The recipient simply enters the password when prompted.
Keep a record of the password you set. If you lose it, recovering access to the encrypted PDF is not straightforward.
The document you're protecting never gets uploaded. When you use an online PDF password tool that requires a server upload, the document you're trying to protect is exposed to that server before protection is applied — defeating the purpose for truly sensitive files. This tool applies the password locally using pdf-lib in your browser. The only version that ever exists on a server is the one you choose to send.
Full PDF standard permissions control. Beyond a simple open password, the PDF standard allows fine-grained permissions: you can allow viewing but block printing, or allow printing but block copying text. These controls are enforced by all compliant PDF readers — useful for distributing read-only reference documents or proof copies.
No account, no watermarks, no file limits. Many free online PDF tools watermark outputs or cap free usage. This tool has none of those restrictions — protect as many PDFs as you need.
Is my PDF uploaded to a server?
No. The password is applied locally using pdf-lib, a JavaScript library running inside your browser. Your document never leaves your device.
What is the difference between an open password and a permissions password?
An open password is required to view the document at all. A permissions password controls what the viewer can do once they've opened it — printing, copying, editing. You can set either or both independently.
Will it work in Adobe Acrobat, Preview, and other readers?
Yes. The protected PDF follows the PDF standard and is compatible with Adobe Acrobat, Apple Preview, Chrome's built-in viewer, Firefox, Foxit, and virtually all other compliant PDF readers.
Can I restrict printing or copying?
Yes. The permissions settings let you block printing, text copying, and editing independently. These restrictions are enforced by compliant PDF readers when a permissions password is set.
What if I forget the password?
PDF encryption is designed to be hard to reverse. If you lose the password, recovering access is difficult. Always note down the password before downloading the protected file.
Is there a file size or page limit?
There is no server-side limit. Processing happens in your browser, so very large PDFs may take a moment but will complete without issue on most modern devices.
Free. Instant. No sign-in. Upload your PDF, set a password, download the secured file.
Open Password Protect PDF on Doathingy.com →