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Merge PDFs

Free
Combine multiple PDFs into one in the order you choose. Drag to reorder, runs in your browser via pdf-lib.

What you'll get: a single combined PDF in the exact order you set — drag to reorder, with a first-page thumbnail next to each input so you can confirm what you're merging. Runs entirely in your browser via pdf-lib. For another use, try Split PDF.

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Stays in your browser
Free tools run fully on-device — nothing is uploaded to a server.
No watermarks
Clean output, no branding, no daily limits.
Free forever
No signup required. Seriously.

Why people merge PDFs

Merging is the most-searched PDF tool on the web. Whether you're consolidating a sign-off package, building a single deliverable from multiple drafts, or stitching scanned pages back together, the workflow is the same — and we run it in your browser.

Expense reports
Combine receipts, invoices, and a coversheet into one PDF for finance. Order matters — drag to reorder so the coversheet stays on top.
Multi-author drafts
When each contributor sends their section as a separate PDF, merge them into a single deliverable without rewriting layout in Word.
Scanned documents
Phone scanners often save each page as its own PDF. Merge them back into one document so it can be filed, signed, or emailed as a unit.
Lecture notes & study packs
Combine lecture handouts, slide exports, and reading PDFs into one revision file. Keeps the term’s material in one place.
Audit packages
Compliance reviews often want every supporting document in one bundle. Merge ledger statements + invoices + reconciliations into a single auditor PDF.
Sign-off packets
Sales contracts, statements of work, NDAs — merge into one signing flow so the recipient gets a single attachment instead of five.

How Merge PDFs works

Three steps, no signup, no uploads.

  1. STEP 1
    Drop your PDFs
    Up to 100 MB each, no count limit. PDFium renders a small first-page thumbnail next to each input so you can confirm what you uploaded. Files stay in your browser — pdf-lib runs as JavaScript, no upload.
  2. STEP 2
    Reorder if needed
    Drag list items to set the final order, or use the up/down buttons. Order = output sequence; first listed becomes page 1.
  3. STEP 3
    Click Merge & download
    We copy every page from each input into a fresh PDF, save with object streams (smaller output), and trigger the download.

What makes pdfcraft ai different

  • Same engine Chrome uses
    PDFium is Google's PDF engine — the one that powers Chrome's built-in PDF viewer. We compile it to WebAssembly so it runs in your browser at near-native speed.
  • 100% local processing
    Most free PDF tools upload your file to a server, process it, and stream the result back. We don't. Your file lives in your browser tab and never touches our infrastructure. Verifiable in your browser's Network panel.
  • No watermark, no signup, no daily limit
    Convert 1 PDF or 1,000. We don't gate on volume because there's nothing to gate on — the engine runs on your machine.
  • Honest about limitations
    When something the tool can't do (encrypted PDFs, cross-reference streams), we tell you clearly instead of failing silently. Same for partial results: sampled vs exact, embedded vs not.
  • Open standards, free engines
    PDFium is BSD/Apache licensed (free for any use). We don't pay vendor license fees and pass that savings on to you (and to ourselves) as a free, ad-supported tool with no upgrade-to-pro pressure.

Frequently asked questions

Is anything uploaded?
No. pdf-lib is a pure-JavaScript library that runs entirely in your browser. There’s no upload, no server processing, and no copy of your file on our infrastructure. You can verify in DevTools → Network tab — there’s no outbound request when you click Merge.
Will the output be watermarked?
No. Merge is free, no signup, no watermark. The output is a clean PDF ready to share. We make money on AI tools (chat, summarize, translate, etc.); the free utility tools are loss leaders to bring you here.
What about bookmarks, links, and form fields?
Page content is preserved exactly. Internal bookmarks and cross-page hyperlinks are NOT remapped to the new page positions — pdf-lib v1.17 doesn’t support that. If your inputs have heavy bookmark structures, expect them to point to the wrong pages in the merged output. Most users aren’t affected; flag it if you are.
Is there a limit on file count or size?
100 MB per input. No hard limit on count, but the browser tab will get sluggish past about 200 MB total. For massive merges, split the work: merge 5 inputs into one, then merge that with the next 5, and so on.
Will encrypted PDFs work?
Owner-restriction-only PDFs (no-print, no-copy, but no password to open) work fine. PDFs that require a password to open will fail — unlock them first with our Unlock PDF tool, or with Adobe Acrobat / the source app, then merge.
Why does the output file feel bigger than the inputs combined?
Each input PDF has its own embedded fonts, images, and metadata. When merging, those resources can’t always be deduplicated across inputs (pdf-lib doesn’t fingerprint resources across documents). The output is correct — it’s just less optimized than a single document authored from scratch. For aggressive shrinking, run a server-side compressor afterwards.

Want to split PDFs instead?

Split PDF turns one big PDF into multiple smaller files — by every page, custom ranges, or fixed chunks. Same in-browser pdf-lib engine.

Try Split PDF

Related PDF tools

Other tools in the Organize category — built on the same private, in-browser pipeline.

Use cases for this tool

Step-by-step workflows that put this tool to work.

How to combine bank statements into one PDF for your accountant
Stitch 12 monthly statements into one searchable, OCR'd PDF in under 5 minutes.
How to combine thesis chapters into one submission-ready PDF
Cover, abstract, chapters, references, appendices — one file, with bookmarks, page numbers, and TOC.
How to translate an employee handbook into 5 languages with consistent layout
One source PDF → 5 language-specific PDFs, layout preserved, terminology consistent.
How to prepare exhibits for a court filing
Combine, Bates-number, and archive your exhibits into one court-ready PDF.
How to build a new-hire onboarding pack as one PDF
Combine your handbook, policies, and forms into one clean, fillable onboarding PDF.
How to convert Markdown notes into a clean PDF
Turn .md files into a formatted, page-numbered PDF you can share or print.
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