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Combine PDFs to 150MB Files — Browser, No Upload

Published 2026-05-02

7 min read

Why merge PDFs locally?

Legal, tax, and HR PDFs often contain PII. The moment you upload them to a “free merge” site, you have lost custody — the file transits TLS to a stranger’s object storage.

ExactPDF merges in your tab using WebAssembly + pdf-lib. Disconnect Wi‑Fi after the page loads: merging still works.

Who this is for

  • M&A teams stitching diligence folders on a VPN
  • Students merging scanned chapter PDFs for printing
  • Home offices combining utility bills + receipts for accountants

    • Step-by-step

  • Open Merge PDF.
  • Drag every file — each can be up to ~150 MB on modern laptops.
  • Reorder thumbnails so exhibits read 1 → n.
  • Download the single combined output — no watermark, no signup.

    • Start merging now →

    See also: Merge PDF free — no upload and Why local PDF processing is more secure.

    Free Tool
    Try Merge PDF

    Merge large PDFs locally — up to ~150 MB each, no cloud upload.

    Open Tool
    100% private — runs in your browser

    Frequently asked questions

    Can I merge large PDFs without uploading them?

    Yes. ExactPDF combines PDFs entirely in your browser using WebAssembly and pdf-lib. Open DevTools → Network while merging: you will see zero file uploads. That is the privacy difference versus Smallpdf, iLovePDF, and Adobe online.

    What file size can I merge?

    Each input PDF can be up to roughly 150 MB on modern hardware — the same headroom advertised on the Merge PDF tool. Total batch size depends on available RAM, but there is no artificial 2-tasks/day cap.

    Will quality drop when I merge?

    No re-compression happens during a straight merge. Pages are concatenated; vector text and embedded images stay as authored unless you run a separate compress step afterwards.

    Does this replace Adobe Acrobat combine?

    For merging locally without subscription, yes. Acrobat Pro still wins on preflight print production and redaction legal certs — but for “stitch these PDFs together privately”, browser merge is enough.

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