Password Protect PDF

Password protect PDF files online for free. Add an open password, encrypt locally, and download a locked PDF — no upload.

  • Free
  • No Signup
  • No Daily Limit
  • Browser-Based
  • No Server Upload
  • Fast Processing
  • Works on Mobile

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4.9/52,374 votes

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How to password protect or lock a PDF

Upload an unprotected PDF, enter and confirm your password, then click Password protect PDF. Encryption runs locally before download.

Searching password protect pdf, lock pdf, or encrypt pdf? SnapKit adds open-password protection in your browser.

Why choose SnapKit? Our tools are 100% Private, No Server Upload, Instant Browser-Based, with No File Size Limit.

When should you use this tool?

Password protect PDF files online for free. Add an open password, encrypt locally, and download a locked PDF — no upload.

Is my data uploaded to the server?

No. SnapKit processes your files entirely in your browser using client-side WebAssembly, Canvas, and Web APIs. Your documents, images, and audio never leave your device, and we do not store uploads on our servers.

Why choose SnapKit?

Every tool is built around four promises: privacy, speed, freedom, and accessibility. No cloud pipeline — just your browser and your files.

  • 100% Private — No Server Upload

    Files are processed on your device with client-side WebAssembly and Canvas. No bytes are sent to our servers.

  • Instant Browser-Based speed

    Skip slow uploads and downloads. Your CPU and GPU do the work locally for near-instant results.

  • No File Size Limit — Free forever

    No registration walls, no watermarks, and no arbitrary caps. Use ringtone, video, PDF, and image tools freely.

  • Works on every device

    iPhone, Android, Windows, and Mac browsers are all supported with the same private, instant experience.

Frequently asked questions

What type of PDF password is added?

An open password that readers must enter before viewing the document.

Is password protect pdf free?

Yes. Locking PDFs is free with no account required.

Is my password sent to a server?

No. Encryption happens entirely on your device.

Is my data safe with this tool?

Yes. All processing runs 100% on your device using client-side WebAssembly, Canvas API, and browser APIs. No bytes from your files are transmitted to our servers — zero server upload, absolute privacy.

Why is the processing speed so fast?

Because your file never leaves your browser. SnapKit uses WebAssembly and Canvas to harness your device CPU and GPU directly, skipping slow network upload and download steps.