Merge PDF files
Combine multiple PDFs into one. Fast, free and 100% private, works offline, — your files never leave your browser.
Drop PDF files here
or click to choose from your device
Choose PDF filesHow to merge PDFs
- Click "Choose PDF files" or drag PDFs into the box above.
- Reorder by clicking the up/down arrows on each file.
- Click "Merge PDFs" — your merged file downloads instantly.
What is "Merge PDF"?
Merging a PDF is the simple act of combining two or more PDF files into a single document, in a specified order, while preserving the original pages exactly. The merged file behaves like any other PDF — searchable, printable, signable, shareable — and the page count is the sum of the inputs.
Under the hood, every PDF is a tree of "page objects". Merging copies those objects from each source PDF into a new container PDF, then writes the result out as a fresh, self-contained file. Because the original page data is copied byte-for-byte (rather than being re-rendered), fonts stay sharp, vector graphics stay vector, and form fields and digital signatures are preserved where the structure allows. There is no quality loss, no resampling, and no need to flatten anything for a basic merge.
When to use Merge PDF
A few situations where combining PDFs solves a real problem:
- Loan, visa, and rental applications. Most banks and consulates ask you to upload a single PDF containing your passport, payslips, bank statements, and reference letter. Merging them in the right order avoids the "we couldn't open file 3" follow-up email.
- Court bundles and legal exhibits. Lawyers — and self-represented litigants — are often required to file all evidence as one paginated PDF, in the order the witness statements reference. Merging beats stapling scans together page by page.
- Multi-chapter writing. Writers who export each chapter from Word, Scrivener, or Google Docs as a separate PDF can merge them into one manuscript for editor handoff or self-publishing on platforms like Amazon KDP.
- Expense reports. Receipts photographed on a phone (often saved as individual PDFs by camera apps) can be merged into one finance-friendly file that matches a single expense claim.
- Scanned documents. Older multi-page scanners that produce one-PDF-per-page can be consolidated into a single readable file before archiving.
- Property and tax records. Annual statements, council rates, insurance documents, and inspection reports often arrive separately and benefit from being archived as one merged file per year.
How PDFtez merges your PDFs (under the hood)
PDFtez's Merge tool runs entirely inside your browser. When you drop files onto the page, your browser reads them into memory using the standard File API — at no point are the files sent to a server, and nothing about them is logged. The merge itself is performed by pdf-lib, an open-source JavaScript library that parses, manipulates, and writes PDF binary structures directly in the browser. Pages from each input PDF are copied into a new in-memory PDF document in the order you specify, and the result is saved using the browser's URL.createObjectURL to trigger a local download.
Once you close the tab, your files are gone — there is no temporary copy on any disk. If you want to verify it for yourself, open your browser's DevTools → Network panel while you merge: you will see no outgoing requests carrying your PDF data.
How is PDFtez Merge different from other online PDF mergers?
Most "free" online PDF tools — iLovePDF, SmallPDF, PDF24, Adobe's online merger, and the long tail of clone sites — work the same way: you upload your file to a server, the server merges it, you download the result. That model means your file is briefly on someone else's infrastructure, governed by their privacy policy and retention rules. It also means daily limits, file-size caps, and constant upgrade prompts pointing toward a paid tier.
PDFtez does the merge on your device. There is no upload, no sign-in, no daily limit, no premium tier, and no hard cap on the number of files you can combine beyond what your browser's memory allows. The trade-off is that very large files (200 MB or more) may briefly slow your browser — that is the price of keeping your data private.
Frequently asked questions
Is there a file size or page count limit?
There is no hard limit imposed by PDFtez. Most files under 100 MB merge in a second or two on a modern laptop. Files over 200 MB may briefly slow your browser depending on available RAM. There is no cap on the number of PDFs you can merge in a single batch.
Can I merge password-protected PDFs?
Yes — PDFtez attempts to read encrypted PDFs in compatibility mode and will merge them if the encryption allows page extraction. If a file is locked tightly with owner-password restrictions, use the Protect PDF tool to remove the password first (you will need to know it), then merge.
Will the merged file lose quality?
No. Merging copies page data exactly as it exists in the source files — there is no re-rendering, no recompression, and no resampling. Vector graphics stay vector, text stays selectable, and embedded fonts remain intact.
Does it preserve bookmarks, signatures, and form fields?
Bookmarks from individual source files are not currently carried over — a known limitation we may address in a future update. Digital signatures will be preserved structurally but, because the file is modified, they will show as "signature invalid" — this is true for every PDF merger, including Adobe Acrobat. Form fields are preserved.
Does it work on mobile?
Yes. PDFtez works on any modern mobile browser including Safari on iOS and Chrome on Android. The interface is touch-friendly. The only practical limit on mobile is your device's available memory, so very large files may merge more slowly than on a laptop.
Are my files safe? Where do they go?
Your files stay on your device. The merge runs entirely offline in your browser's memory using JavaScript. No file data is uploaded to any server, no copy is stored anywhere, and nothing is logged. You can verify this in your browser's DevTools by inspecting outgoing network requests while you merge.