What encryption is used?

Standard PDF encryption (RC4 / AES) via the built-in PDF security handler — the same scheme Adobe Acrobat, Preview, and every other PDF reader understands. Any reader will prompt for the password.

What's the difference between a user password and an owner password?

The user (open) password is what someone types to open the file. The owner password is only needed to change the permissions or remove the encryption. If you leave it blank, we reuse the open password as the owner password.

Can I lock printing, copying, or editing?

Yes. Turn on "Also restrict what readers can do" and pick which actions are allowed. Note: permission flags are honored by well-behaved PDF readers; a determined attacker with a cracked owner password can still bypass them. Use a strong password for real security.

If I lose the password, can you recover it?

No. The encryption key is derived from your password on your device — we never see it. There is no recovery, so store the password safely (e.g. in a password manager).

Can I remove a password from a PDF I already own?

Not with this tool. This one only adds protection. An unlock/remove-password tool is on the roadmap.

What's the file size limit?

Free users can protect PDFs up to 10 MB. Pro users are only limited by their device's memory.

Password-protect a PDF

Encrypt a PDF with a password and restrict printing, copying, or editing — free, private, and 100% in your browser.

Drop a PDF, or click to browse

PDF only · up to 10.00 MB on free · Pro unlocks larger files

What people use it for

Send tax returns, payslips, or bank statements to your accountant with a password.
Share NDAs, contracts, and offer letters that only the recipient can open.
Protect medical records or lab results before emailing them to a patient or clinic.
Lock printing and copying on a proposal or pitch deck sent to a prospect.
Password-protect a scanned ID or passport copy before uploading to a landlord or bank.
Add a password to invoices or quotes shared over Slack, WhatsApp, or email.

This is a free PDF password protector that lets you add a password to a PDF right in your browser. Drop the file, choose a password, and download an encrypted copy that any PDF reader — Adobe Acrobat, Preview, Chrome, Edge, Foxit — will refuse to open without it. There is no upload, no watermark, no signup, and no email required.

If you have been searching for how to password-protect a PDF online free, encrypt a PDF, lock a PDF file, or make a PDF read-only, this tool covers all of it. You can set a simple open password so only people with the password can view the document, or turn on advanced restrictions to disable printing, copying text, editing, or annotating the PDF. It is the same PDF security model Adobe Acrobat uses — just free, and running entirely on your device.

Because everything happens locally with WebAssembly, sensitive documents — contracts, NDAs, tax returns, medical records, payslips, scans of IDs — never leave your computer. That makes it a safer choice than the typical "protect PDF online" service that quietly ships your file to a third-party server. Use it to secure a PDF with a password before emailing it, uploading it to a client portal, or sending it over Slack, WhatsApp, or Signal.

How it works

1
Drop your PDF
Drag a PDF into the box above, or click to browse. It stays on your device.
2
Choose a password
Pick a strong password to open the file. Optionally restrict printing, copying, or editing with an owner password.
3
Download the protected PDF
We encrypt the file locally and hand you a copy that any PDF reader will prompt for the password to open.

Frequently asked questions

No. Encryption runs entirely in your browser using pdf-lib. The file, the password, and the encrypted output never leave your device.

Want this converter on your website?

Pro members can embed any Minitooler converter on their own site — styled to match, with no branding beyond a small credit link. One iframe, unlimited use, still 100% in the browser.

Unlock embeds — $5/mo

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Theme

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Text color

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Embeds are a Pro feature

Upgrade to unlock a customizable iframe snippet you can paste into any website — colors, theme, and size all tuned to match your brand.

Go Pro — $5/mo