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Merge PDF

Combine multiple PDFs into one file in seconds.

How it works

  1. 1Open Merge PDF and drop two or more PDF files into the workspace.
  2. 2Wait for page counts to appear so you can confirm each file loaded cleanly.
  3. 3Drag cards into the order you want in the final document.
  4. 4Remove any file you added by mistake, then run merge.
  5. 5Download the combined PDF and keep or discard the originals as you prefer.

About

Merge PDF files online without uploading. StackPDF joins documents in your chosen order entirely in your browser — ideal for contracts, reports, and scanned packets.

Unlike cloud mergers that send every page to a remote server, processing stays on your device. Drag files into the sequence you need, run merge, and download one combined PDF. Text stays selectable and images keep their original quality because pages are concatenated, not re-rasterized.

Use it when you need a single attachment for email, a portal upload, or an archive packet — without an account, a free-tier merge quota, or a privacy tradeoff.

Common use cases

  • Combine a signed contract with annexes into one email attachment
  • Join phone scans of receipts into a single expense PDF
  • Assemble report chapters exported as separate PDFs
  • Stack cover letter, CV, and certificates for a job portal
  • Build a court or compliance packet without sending files off-device

Why merge PDFs in the browser

Cloud “free PDF merger” sites are simple: upload, wait, download. The cost is that your bytes sit on someone else’s disk — even briefly — and free tiers often cap size, page count, or daily jobs. Browser-local merge avoids that path entirely for one-off packets you would not email to a stranger.

StackPDF loads PDF tooling in the page, keeps files in memory on your device, and builds the combined document there. After the app loads, a flaky network does not stop the merge itself.

Order, quality, and what merge does not change

Each source contributes its pages in full. Putting the cover letter first and exhibits later is a drag-and-drop step before you run merge — faster than splitting the result later.

Because pages are not re-rendered as images, selectable text, vector graphics, and embedded image resolution stay as they were in the sources. If a scan was blurry going in, it will still be blurry going out.

When a cloud merger might still make sense

Shared team libraries, automated server pipelines, or multi-user review workflows may still need a cloud suite. For personal legal packs, HR forms, medical packets, and homework bundles, local merge is usually enough: same combined PDF, no upload.

If you later need OCR on a huge archive, e-sign routing, or long-term shared storage, use a service built for that — and keep StackPDF for the private combine step on your machine.

FAQ

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