To password protect a PDF, open Protect PDF, add the file, type the password it should require, and press PROTECT. The copy you download is encrypted with AES-256 and asks for that password every time it's opened, in any PDF reader. Taking the password off again is the same job in reverse: Unlock PDF takes the password once and hands back a copy that never asks for it. The one thing to settle before you start is where the password will live, because nobody — us included — can recover it once it's lost.
This covers:
- The three steps, start to finish
- Choosing a password that actually protects the file
- What the password does, and what it doesn't
- Locking a batch of files at once
- Removing the password again, and changing it
- What to do when the password is gone
- What to do when something goes wrong
Password protect a PDF in three steps
- Open Protect PDF. Nothing to install and no account needed to start.
- Add the PDF. Drop it onto the drop zone, or pick it from your device, Google Drive, or Dropbox. It uploads, passes a brief security check, and appears in the list.
- Type a password and press PROTECT. The password goes in the box under the file list, and the button won't run until there's something in it. A moment of Encrypting… later, the success card shows the new file: Download it, or save it straight to Google Drive or Dropbox.
The copy comes back as report (protected).pdf, and the file you uploaded is left exactly as it was. That's worth knowing before you file anything away: you still have an unlocked version, which is your fallback if the password ever goes missing — and also the copy that needs keeping somewhere only you can reach.
Got a file that shouldn't open for just anyone?
Try Protect PDFChoose a password that holds up
A locked file isn't like a login. Nothing counts failed attempts, and nothing locks anyone out after three wrong tries: whoever has the file can try passwords against it as fast as their computer allows, for as long as they like. The encryption itself isn't the weak point — AES-256 is what banks and governments use — so the password is where the protection is won or lost.
- Make it long. Three or four unrelated words are far harder to guess than a short word with a number on the end, and easier to read out over the phone.
- Send it separately. A password in the same email as the attachment protects nothing. Send it by text message, say it on a call, or hand it over in person.
- Store it where you'll find it. A password manager is the right place. The protected copy can't be opened without it — not next week, and not in three years when the file resurfaces.
What the password does — and what it doesn't
What it does:
- Encrypts the contents. The pages, text, and images are scrambled with the password, so a locked file isn't a file with a "please ask" flag on it — without the password there's nothing readable inside.
- Stays with the file wherever it goes. Forwarded, copied to a shared drive, synced to a phone, left on a laptop in a bag: the copy is still locked, because the lock is in the file itself rather than in wherever you first sent it.
- Opens in any current PDF reader. Acrobat, Preview, a browser tab, a phone — each asks for the password once and then shows the document as normal. The recipient installs nothing.
What it doesn't do:
- It doesn't restrict printing, copying, or editing separately. This tool sets an open password and nothing else. Anyone who has the password can print the file, copy text out of it, edit it, and take the password off again with Unlock PDF — the same rights you have. Putting a print or copy restriction on a file that should still open freely is a different kind of protection, and not something this tool does.
- It doesn't prove who made the file. A password says nothing about who wrote or approved a document. For that you want a signature — how to sign a PDF covers what a drawn signature is and isn't.
- It can't be undone without the password. Not by you, not by us. The section further down covers what to do if it's gone.
Protect several PDFs at once
Add the whole batch and the checkboxes decide what goes in, the same way they do for every tool:
| What you select | What gets protected |
|---|---|
| Nothing ticked | Every file in the list |
| Some files ticked | Only those files |
The PROTECT button shows the count in brackets — PROTECT [ 3 ] — so you can confirm before you commit. Every file in the run is locked with the same password and becomes its own protected copy under its own name. More than one result arrives as a single zip, and the success card says how many files are inside.
For different passwords on different files, run them one at a time: the password box applies to the whole run. If one file in the batch couldn't be processed — it was already locked, say, or damaged — the rest still finish, and the card names the file that was skipped.
Without an account there's a cap on how many files the workspace holds at once. Sign in to raise it, or work in batches; pricing covers the higher limits.
Remove the password from a PDF
Typing a password on every open gets old fast, and some files were only ever locked for the trip: the bank statement that arrives locked every month, payslips filed into an archive that's already secure, the contract you locked yourself last year and now need to edit. Unlock PDF makes an open copy of a file you can already open.
- Open Unlock PDF. It's the one page that accepts a locked file — every other tool declines one at upload with seems to be broken, invalid or encrypted, because nothing can read the pages without the password.
- Add the locked PDF. It's stored exactly as uploaded; no preview thumbnail appears, for the same reason.
- Type the password it opens with and press UNLOCK. A moment of Unlocking… later, the copy is ready as report (unlocked).pdf. It carries no encryption of any kind: no open password, and no printing, copying, or editing restrictions either.
A file that opens without asking but refuses to print or copy is locked with permissions rather than a password. Unlock clears those as well. The password box still has to have something in it for the button to work, so type the owner password if you have it — or any text if the file opens without one.
What the tool never does is guess. It removes protection with the password, not around it: a wrong password stops the job with an error, and no amount of retrying changes that. If the password is lost, the encryption is doing exactly what it was designed to do.
The unlocked copy is a working copy
Once the encryption is off, everything else works again: compress it, merge it with other documents, convert it to Word, or sign it. Finished, and it should be locked again? Protect PDF puts a new password on in seconds.
Change the password on a PDF
A PDF carries one password at a time, so changing it is two runs: unlock the file with the old password, then protect the unlocked copy with the new one. Protect PDF won't accept a file that's still locked — it's declined at upload — which is why the order matters.
The name picks up a suffix at each step, so statement (unlocked) (protected).pdf is what you end up with; rename it before you file it.
If you've forgotten the password
The honest answer first: a lost password cannot be recovered. Not by the tool, not by us, not by anyone — that is what encryption means, and any service claiming otherwise is either guessing short passwords or not telling the truth. What actually helps:
- Look for the original. Protecting a file makes a copy; the file you uploaded was left as it was. If you locked it yourself, the unlocked version is usually still wherever it started.
- Check the message the file came with. Statements and payslips that arrive locked are often accompanied by a note explaining what the password is made of — a date of birth, a postcode, a customer number.
- Ask the sender. A fresh copy, or the password sent another way, is quicker than anything else.
- Check your password manager. If you stored it, it's there under the file's name or the recipient's.
If none of that turns it up, the file stays locked. A long password on a strong cipher is designed to survive exactly this.
When protecting or unlocking goes wrong
| What you're seeing | What happened | Fix |
|---|---|---|
| "…seems to be broken, invalid or encrypted" when adding a file to Protect PDF | The file is already locked — a PDF holds one password at a time — or it's damaged | Locked: remove the current password with Unlock PDF first, then protect the copy with the new one. Damaged: try Repair PDF |
| The PROTECT or UNLOCK button doesn't respond | The password box is empty | Type the password, then press the button |
| "Oops… Error while processing one of your files" on Unlock PDF | The password didn't match the file | Check for a typo or Caps Lock and try again. Several files in one run all get the same password, so a file with a different one needs its own run |
| A file in the batch was skipped | Its password was different, it was already locked, or it couldn't be read | The card names it — run it on its own |
| The downloaded file still asks for a password | You opened the original rather than the new copy | The unlocked copy is the one named (unlocked) |
| Another tool refuses the file | Every tool but Unlock declines a locked PDF at upload | Unlock it first, then run the tool on the copy |
| The editor says the PDF can't be saved or exported | The editor can open a locked file but can't rebuild it | Unlock it, sign or edit the copy, then protect it again — how to sign a PDF |
| Instead of running, the button says you've reached your free limit | There's a cap on how many jobs run before a plan is needed | See pricing for what the plans include |
| Can't add any more files | Without an account there's a cap on how many files the workspace holds at once | Sign in, or work in batches; see pricing for higher limits |
Where protecting fits with the other tools
Protection works best as the last step, because a locked file can't go through anything else. Finish the document, then lock it:
| You want to | Tool |
|---|---|
| Combine the pieces first | Merge PDF — how to merge |
| Make it small enough to email, then lock it | Compress PDF — how to compress |
| Sign it before it's locked | Edit PDF — how to sign a PDF |
| Send only some of its pages | Split PDF or Extract PDF Pages — how to split |
| Unlock a received file so it can be edited or converted | Unlock PDF, then Edit PDF or PDF to Word |
| Turn a Word document into a PDF you can then lock | Word to PDF — how to convert Word to PDF |
See all PDF tools.
Frequently Asked Questions
How do I password protect a PDF online?
Open Protect PDF, add the file, type the password it should require, and press PROTECT. The copy you download is encrypted with AES-256 and asks for the password in any PDF reader — Acrobat, Preview, a browser, or a phone — with nothing for the recipient to install.
Does password protecting a PDF stop people from copying or printing it?
Not separately. The tool sets an open password only: without it, the file can't be opened at all, and with it, the reader can print, copy, edit, and remove the password. The password is the door, not a set of rules for what happens inside.
What happens if I forget the password?
It can't be recovered by anyone, including us. Protecting a file makes a copy and leaves the original untouched, so check where the unlocked version started; otherwise check the message the file came with, your password manager, or ask the sender for a fresh copy.
Can I remove a password from a PDF without knowing it?
No. Unlock PDF removes protection from a file you can already open — it takes the password once and returns a copy that never asks for it. It does not crack, guess, or bypass anything.
Does unlocking remove printing and copying restrictions too?
Yes. The unlocked copy carries no encryption at all, so an open password and any restrictions on printing, copying, or editing go together.
Can I use a different password for each file in a batch?
One run uses one password for every file in it. To give files different passwords, run them one at a time; each finishes in seconds.
