How do I put a password on a PDF for free?

Choose the PDF, type an open password twice and click Protect PDF & download. The downloaded copy asks for that password in Adobe Acrobat Reader, Chrome, Edge, Firefox and other PDF readers. There is no signup and no watermark.

What is the difference between the open password and the permissions password?

The open password is needed to view the PDF; without it the content stays encrypted. The permissions password (owner password) only controls what people can do after opening it, such as printing, copying and editing. They must be different if you use both.

Can I stop people printing or copying my PDF?

Yes. Tick Apply these restrictions and block printing (or allow low-resolution printing only), copying, editing, comments, form filling or page changes. Adobe Acrobat, browsers and most readers respect these settings, but some software can ignore them, so use an open password for anything confidential.

What encryption does this tool use?

AES-256 by default, the strongest method in the PDF standard, supported by Acrobat X and later and all current browsers. AES-128 is available for very old readers. RC4 is not used.

I forgot the password. Can you recover it?

No. The password is not stored anywhere and an AES-256 encrypted PDF cannot be opened without it. Keep your original unprotected file and save the password in a password manager.

Can I protect several PDFs at once?

Yes. Add up to 20 PDFs of up to 100 MB each. They all get the same password and settings, and download together as a ZIP.

Are my files and passwords stored?

No. The PDF and passwords are sent over HTTPS, encrypted on our server in memory for your request, then discarded. Files are not kept and passwords are not logged. Encryption does not run in your browser.

Password Protect PDF

Part of PDF tools: See all PDF tools.

What is PDF Password Protect?

A free tool to password protect PDF files. Set an open password so only people you choose can view the PDF, encrypted with AES-256 (or AES-128 for very old readers). Optionally restrict printing, copying text, editing, comments, form filling and page changes with a separate permissions password. Protect one PDF or up to 20 with the same settings; each locked file is opened again and checked before you download it.

How to use PDF Password Protect

Choose one or more PDF files, or drag them onto the box (up to 20, 100 MB each).
Type an open password twice, or click Generate strong password.
Optional: open Restrict printing, copying and editing, tick Apply these restrictions and choose what to allow.
Keep AES-256 encryption unless the file must open in very old software.
Click Protect PDF & download, then open the file once to confirm your password works.

Why use this tool?

Many free PDF lock tools use one password for everything, so the print and copy restrictions they promise do nothing. This tool keeps the open password and the permissions password separate, uses AES-256, refuses files that are already locked instead of silently changing them, and verifies every result before sending it, so you know the password and settings really work.

FAQ

How do I put a password on a PDF for free?: Choose the PDF, type an open password twice and click Protect PDF & download. The downloaded copy asks for that password in Adobe Acrobat Reader, Chrome, Edge, Firefox and other PDF readers. There is no signup and no watermark.
What is the difference between the open password and the permissions password?: The open password is needed to view the PDF; without it the content stays encrypted. The permissions password (owner password) only controls what people can do after opening it, such as printing, copying and editing. They must be different if you use both.
Can I stop people printing or copying my PDF?: Yes. Tick Apply these restrictions and block printing (or allow low-resolution printing only), copying, editing, comments, form filling or page changes. Adobe Acrobat, browsers and most readers respect these settings, but some software can ignore them, so use an open password for anything confidential.
What encryption does this tool use?: AES-256 by default, the strongest method in the PDF standard, supported by Acrobat X and later and all current browsers. AES-128 is available for very old readers. RC4 is not used.
I forgot the password. Can you recover it?: No. The password is not stored anywhere and an AES-256 encrypted PDF cannot be opened without it. Keep your original unprotected file and save the password in a password manager.
Can I protect several PDFs at once?: Yes. Add up to 20 PDFs of up to 100 MB each. They all get the same password and settings, and download together as a ZIP.
Are my files and passwords stored?: No. The PDF and passwords are sent over HTTPS, encrypted on our server in memory for your request, then discarded. Files are not kept and passwords are not logged. Encryption does not run in your browser.

What this PDF password tool does

This page adds password protection to a PDF so that only people you give the password to can open it. You type an open password (also called a user or document open password), choose how strong the encryption should be, and download a locked copy of your file. When someone opens the copy in Adobe Acrobat Reader, a web browser, macOS Preview or a phone app, they are asked for the password first. Without it the pages, the text, the images and even the document title stay scrambled.

You can also restrict what people may do once the file is open: block printing or allow only low-resolution printing, stop text and images being copied, block editing, comments, form filling, or inserting, deleting and rotating pages. These restrictions are protected by a second password, the permissions password (in Acrobat it is called the owner password). You can use restrictions together with an open password, or on their own if you want anyone to be able to read the file but not copy or print it.

You can protect one PDF or up to 20 at once with the same settings, each up to 100 MB. A single file downloads straight away; several files download together as a ZIP. Before any file is sent back to you, the tool opens the encrypted copy again and checks that it really needs the password, that the password you typed opens it, that every page is there and that the permissions match what you chose. If a check fails, you get an error instead of a file that might not work.

How to password protect a PDF

Choose your PDF files or drag them onto the box. You can remove any file from the list before you start.
Type an open password and type it again to confirm it. The meter under the box shows roughly how hard it would be to guess. If you prefer, click Generate strong password to create a random 16-character password; it is filled into both boxes and copied to your clipboard if your browser allows it.
If you also want to limit printing, copying or editing, open Restrict printing, copying and editing, tick Apply these restrictions and choose what to allow. You can type your own permissions password or leave it empty to have a random one created for you.
Leave the encryption on AES-256 unless the file must open in very old software.
Click Protect PDF & download. The result box lists each protected file with its page count and size, and shows the permissions password if one was created for you, with a Copy button.

Then open the downloaded file once yourself to make sure you can get in with the password. Send the password to the other person separately from the PDF, for example by phone or text message rather than in the same email.

Open password vs permissions password

PDF files can carry two different passwords, and they do very different jobs. Mixing them up is the most common reason people think a protected PDF is safer than it is.

The open password controls access. The PDF is encrypted with a key derived from it, so a reader cannot show anything until the right password is entered. This is real protection: without the password the content cannot be read, no matter which program is used. How safe it is depends almost entirely on the password. A long random password with AES-256 is far beyond what anyone can guess; a short word or a date can be cracked with free tools in minutes.

The permissions password controls what is allowed after the file is opened. Acrobat, Chrome, Edge, Firefox and most other readers respect the flags and grey out Print, Copy or Edit as you chose. But the flags are a request, not a lock: anyone who can open the file can, with the right software, make a copy without them. Use restrictions to prevent casual copying and printing and to signal how a document should be used, not to protect secrets. If the content itself is confidential, always set an open password.

If you set restrictions and an open password, the two passwords must be different. Someone who opens the file with the open password then gets the restricted view; only the permissions password can change the restrictions in Acrobat. If you leave the permissions password empty, the tool creates a random 24-character one and shows it to you once. Save it if you may want to change the settings later. It is not stored anywhere, so we cannot show it again.

AES-256 or AES-128?

AES-256 is the strongest encryption the PDF standard offers and the default here. It is the method defined in PDF 2.0 and used by Adobe Acrobat X (2010) and later. Current versions of Acrobat Reader, Chrome, Edge and Firefox open it. AES-128 is the older method from Acrobat 7 (2005). It is still secure with a good password, and the only reason to pick it is a very old reader or a system that rejects AES-256.

Older tools sometimes use RC4 encryption, which has known weaknesses. This tool does not offer RC4.

Passwords for AES-256 may contain letters from any language, such as accents, Greek, Cyrillic or Japanese. AES-128 only supports plain keyboard characters, because older readers cannot reliably match other characters. Emoji are refused for both, because several readers cannot open files locked with them. Spaces count as part of the password, and the maximum length is 127 bytes, the PDF limit.

What is protected and what stays the same

With an open password set, everything inside the PDF is encrypted: page text, fonts, images, form fields, bookmarks, attachments and the document properties such as title and author. Someone looking at the raw file sees only scrambled data. The file name is not part of the PDF, so it stays readable; rename the file first if the name itself gives too much away.

The content is not changed. Pages are not turned into images, text stays selectable for people who have the password, and links, bookmarks and fillable form fields keep working. In our tests with multi-page reports, fillable forms, linearized (fast web view) files and PDFs using compressed object streams, the page count, text, links, bookmarks and form values were the same after protection, and the files opened with the password in Chrome's PDF engine, MuPDF, qpdf and pypdf. The file size usually changes by a few kilobytes because the file is rewritten.

How to choose a strong PDF password

Length matters more than anything else. A password of 12 or more characters that mixes upper and lower case letters, numbers and symbols, or a phrase of four or five unrelated words, is very hard to guess. Avoid names, birthdays, phone numbers, company names and common words with a number on the end; these are the first things cracking tools try. The strength meter on this page gives a rough guide: it scores length and character variety, and marks common passwords and simple sequences such as 12345678 as very weak.

If you need to protect files for many people, the password generator can create a batch of strong passwords. Keep the password somewhere safe, such as a password manager. A forgotten open password cannot be reset or recovered by us or anyone else; the only copy of the content you can still read is the original file you protected.

Common uses

People protect PDFs before emailing payslips, tax returns, bank statements, medical letters, contracts, invoices with customer details, scanned passports and ID cards, exam papers and internal reports. Restrictions without an open password suit price lists, brochures and published guides that anyone may read but that you do not want copied into another document or printed in bulk. Accountants and HR teams often protect a batch of files at once with the same password; this tool handles up to 20 in one go.

If your file is too big to email, compress the PDF first and protect it afterwards. To join several documents into one locked file, merge them first, then protect the merged PDF. Protecting has to be the last step, because tools generally cannot change a PDF that is locked.

PDFs that are already protected or signed

If a PDF already has an open password or permission restrictions, the tool does not replace them and tells you so. Remove the old protection with PDF Unlock (you need the current open password if there is one), then protect the file again with new settings.

A digitally signed PDF (one with a certificate signature, not just a picture of a signature) will show its signature as invalid after protection, because the file has to be rewritten. Protect the document first, or ask the signer to sign the protected copy.

Privacy and honest limits

Encryption runs on our server, not in your browser. Your PDF and the passwords are sent over HTTPS, processed in memory for your request and then discarded. Files are not stored, and passwords are not written to logs. If a document is so sensitive that it must never leave your computer, use the password feature in Adobe Acrobat, LibreOffice or Microsoft Word's Save as PDF options instead.

Other limits to know about: the maximum is 20 files of 100 MB each per run; damaged PDFs that cannot be read are refused with a message; the permissions password only applies when restrictions are on; and, as explained above, restrictions are respected by normal readers but are not a substitute for an open password. The tool is free, needs no account and adds no watermark.

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