Password Protect PDF & Unlock PDF — Encrypt, Lock & Restrict Editing
Add a password, encrypt with AES-256, or make a PDF read-only so recipients can view but not edit or copy it — then remove the password again when you need to. Everything runs inside your browser: your file is never uploaded to any server.
These restrictions are enforced by Adobe Reader and most PDF apps. For a document nobody can alter at all, also require a password to open (above).
Only unlock PDFs you own or are authorised to. You must know the password — this tool removes it, it does not crack or bypass unknown passwords.
Password protect PDF files in seconds, directly in your browser. Whether you want to add a password so a document can't be opened without it, or make a PDF read-only so people can review it but not edit or copy it, this free tool does both — and because everything runs on your own device, your file is never uploaded to a server. The one thing worth understanding first is that there are two different ways to password protect a PDF, and picking the right one is what separates a genuinely secure file from one that only looks locked.
How to password protect a PDF
To password protect PDF documents so nobody can open them without the password, use the Protect a PDF tab above and turn on Require a password to open. This encrypts the whole file — the text, images and structure become unreadable until the correct password is entered.
- Drop your PDF onto the tool (or click browse).
- Tick Require a password to open and type a password, then confirm it.
- Leave the encryption at AES-256 unless you have a specific reason to change it.
- Click Protect PDF and download the encrypted copy.
Send the protected file and share the password through a different channel — if you email the PDF, text the password. Anyone who opens it in Adobe Reader, a browser, Preview on Mac or any standard viewer will be prompted for it. You don't need Acrobat, a subscription, or any installed software to create the file, and it's free.
How to make a PDF read-only (protect it from editing)
A very common need is different from a password: you want to send a document someone can review but not change — a signed contract, a quote, a report. To make a PDF read-only and protect it from editing, choose the Review only preset. It opens without any password but is locked against editing and copying, so it stays exactly as you sent it.
If you want the document both uneditable and unopenable without a password, use the Full lock preset instead — that combines a password to open with every editing restriction turned on.
The two kinds of PDF protection — and which one you actually need
PDF security is built on two separate passwords. Choosing correctly is the difference between a document that is genuinely secure and one that only appears to be.
Option 1 — a password to open (real encryption)
This is the open password (sometimes called the user password). When it's set, the PDF is encrypted and cannot be read at all without it. This is true confidentiality: if the file leaks, the contents are still protected. Use it for anything sensitive — payslips, medical records, contracts, anything you'd be uncomfortable seeing forwarded.
Option 2 — permission restrictions (review-only)
This uses the permissions password (the owner password) to switch off actions like editing, copying and printing. The file still opens freely, so it's perfect for a document you're happy for people to see but not change. Be honest with yourself about what this does, though: permission restrictions are advisory. Adobe Reader and every mainstream PDF app respect them, but because the file itself is readable, a determined person using specialised software can strip the restrictions. That's not a flaw in this tool — it's how the PDF format works.
Restrict copying, printing and comments
Under Custom, you control each permission independently — the same granular options the paid desktop apps expose. You can protect a PDF from copying text and images, block printing entirely or allow only low-resolution printing, and turn off comments, form-filling and page rearranging. A typical "share but don't leak" setup is: printing allowed, everything else off. A typical "final version" setup is: editing and page assembly off, printing and copying as you prefer.
AES-256 vs AES-128: which encryption to choose
This tool encrypts with AES — the Advanced Encryption Standard published by the U.S. National Institute of Standards and Technology in FIPS 197 and used to protect classified information. Two key lengths are offered:
| Setting | Best for | Notes |
|---|---|---|
| AES-256 | Everything (the default) | Strongest option; supported by every current PDF reader. |
| AES-128 | Very old readers | Still strong; only needed for legacy software that predates AES-256. |
In practice, leave it on AES-256. Both are far beyond what any casual attacker can break; the weak, crackable option you'll see in older tools (40-bit RC4) is deliberately not offered here because it gives a false sense of security.
How to remove a password from a PDF
Need to go the other way? The Unlock / Remove Password tab strips the password from a PDF you already know the password to — handy when a file arrives locked and you're tired of typing the password every time you open it. To remove password protection from a PDF:
- Open the Unlock / Remove Password tab and drop in the protected file.
- Type the password the PDF currently opens with.
- Click Remove Password and download the unlocked copy.
One honest limit worth stating plainly: this unlocks a PDF you're authorised to open — it removes a password you know. It does not crack, guess or bypass a password you don't have, and no legitimate free tool does. Only remove passwords from documents you own or have permission to change.
Why protecting your PDF in the browser matters
Most online "protect PDF" services upload your file to their servers, process it there, and ask you to trust that they delete it. For a confidential document that's a strange trade — you hand the private file to a stranger in order to keep it private. This tool takes a different route: the encryption engine is downloaded to your browser once, and your PDF is processed entirely on your own device. Nothing is uploaded, nothing is stored, and it keeps working even if you switch your connection off after the page loads.
When you're done here, the rest of your PDF workflow lives a click away: merge PDFs into one file before you lock it, compress a PDF that's too large to email, split or extract pages, or add a watermark before sending. You'll find the full set in the PDF tools collection, part of the free All Tools library.
Frequently asked questions
Can a password-protected PDF still be edited?
It depends which protection you used. If you set a password to open, the file is encrypted and can't be edited (or even read) without it. If you only applied permission restrictions, the file opens normally and Adobe Reader and other standard apps will block editing — but because the file itself is readable, specialised software can remove those restrictions. For a document that truly must not be edited by anyone, add a password to open, which is the Full lock preset in this tool.
How do I make a PDF that people can view but not edit?
Use the Review only preset. It leaves the PDF openable by anyone but switches off editing and copying and flattens any form fields, so the document can be read and printed but not changed. That's the right choice for contracts, quotes and reports you're sending out for review rather than collaboration.
Is it safe to protect a PDF online?
With most services you're uploading a confidential file to someone else's server, which is a real privacy exposure. This tool avoids that entirely by doing everything inside your browser — your PDF and password never leave your device, so there's nothing on a server to leak, cache or misplace. That makes it genuinely safe to use even for sensitive documents.
What's the difference between the open password and the permissions password?
The open password (or user password) is required to open and read the file — it encrypts the document. The permissions password (or owner password) doesn't stop the file opening; it controls what the reader is allowed to do, such as editing, copying or printing. You can set either one on its own or both together. This tool handles the owner password for you automatically when you only need restrictions.
Can I remove a PDF password if I don't know it?
No. The unlock tool removes a password from a file you can already open — meaning you know the password and simply want it gone. It cannot crack or bypass an unknown password, and you should be wary of any tool that claims it can. Only remove protection from PDFs you own or are authorised to modify.
Do I need Adobe Acrobat or any software to password protect a PDF?
No. This runs in any modern browser on Windows, Mac, Linux, Android or iPhone — there's nothing to install and no account to create, and it's free. The person receiving the file doesn't need special software either; the password prompt and the restrictions are part of the PDF standard, so they work in Adobe Reader, Preview, Chrome, Edge and other everyday viewers.
Is AES-256 encryption on a PDF actually secure?
Yes. AES-256 is the same standard used to protect classified government data and is not feasibly breakable by brute force with current technology. The practical weak point is never the algorithm — it's the password. A short or obvious password can be guessed, so use a long, unique one and share it separately from the file itself.
This tool helps you apply standard PDF protection and is provided for legitimate use with documents you own or are authorised to handle. For high-stakes legal, medical or financial confidentiality, follow your organisation's data-security policy and consult a qualified professional.