Merge PDF: Combine PDFs in Your Browser
Free PDF merger that runs entirely in your browser. Drop your PDF files, drag them into the order you want, click Merge, and download the combined PDF. There is no upload to any server, no daily task limit, no file size cap, and no signup. Files stay on your device throughout. The same privacy-first approach we use for our image tools, now applied to PDFs.
Drop your PDF files here, or click to choose
Add 2 or more PDFs. Click pages to pick exactly what to merge. Nothing is uploaded.
🔒 Your PDFs are processed in your browser. Nothing is uploaded to our servers. Open Developer Tools → Network tab to verify.
Six reasons people choose Gizmoop's PDF merger
The differences that matter when you are merging contracts, tax records, or anything else you cannot afford to upload.
100% browser-based
PDFs never leave your device. The merger uses pdf-lib running locally in your browser. Network developer tools confirm zero uploads.
No file count or size limit
Merge 2 PDFs or 200. Combine 5 MB or 500 MB. Unlike iLovePDF's 25-file cap or SmallPDF's 5 MB free limit, Gizmoop has no caps.
Drag-and-drop reordering
Drop files in any order, then drag rows to rearrange before merging. The position number shows the final order at a glance.
Preserves bookmarks and links
Source PDF bookmarks, internal links, and external URLs survive the merge. Form fields are kept where possible.
No signup, no ads-only mode
No account creation, no premium upsell, no daily task limits. Use the tool as often as you want, free forever.
Mobile-friendly
Works on phones and tablets in any modern browser. Touch-friendly drag-and-drop on iOS Safari and Android Chrome.
Who needs to merge PDFs?
Real use cases where combining PDFs into one file solves a real workflow problem.
Submitting academic papers
Combine cover letter, manuscript, references, and supplementary materials into a single PDF for journal submissions. Many journals require a single combined file.
Compiling business reports
Stitch together a financial section, marketing slides, and executive summary from different team contributors into one client-ready document.
Legal exhibits and filings
Merge a brief with supporting exhibits in the correct order for court filings or arbitration submissions. Bates numbering can be added afterward with our Page Numbers tool.
Tax records and receipts
Combine annual receipts, statements, and tax forms into one PDF for accountant submission or personal archiving. Privacy-first matters for financial documents.
Lease and contract bundles
Merge a contract template with addendums, exhibits, and signature pages into one final document ready for signing.
E-book compilation
Combine separately authored chapters into a single book PDF, then add page numbers and a table of contents for distribution.
About merging PDFs
What actually happens, how it differs from competitors, and how to get the best result.
What does merging a PDF mean?
Merging combines two or more PDF files into a single PDF that contains all the pages of each input file, in the order you specify. The pages keep their original formatting, fonts, images, and embedded content. Nothing is re-rendered or re-encoded. The merged file is a normal PDF that can be opened in any reader (Adobe Reader, Preview, Chrome, Firefox) and printed, searched, or edited like any other PDF.
Merging is one of the three most common PDF operations along with splitting and compressing. Office workers merge contracts and exhibits. Students merge thesis chapters and references. Accountants merge receipts into expense reports. The need is universal, which is why over 165,000 people search "merge pdf" every month in the US alone, and millions more worldwide.
How browser-based merging works (and why it matters)
Traditional PDF tools (iLovePDF, SmallPDF, Adobe Acrobat Online) work like this: you upload your PDFs to their servers, the server does the merge, then you download the result. The server then deletes the files after a stated retention period (usually 2 hours for iLovePDF, 1 hour for SmallPDF). This works fine for non-sensitive files. For confidential documents (tax records, medical reports, legal exhibits, financial statements, contracts under negotiation), uploading is a real privacy concern.
Gizmoop's PDF merger uses the pdf-lib JavaScript library. The library runs entirely in your browser. When you click Merge, your browser loads the library code, then processes the PDFs locally using your device's memory and CPU. The merged PDF is created in browser memory and offered as a download. At no point does any of your PDF data travel over the network. You can verify this by opening your browser's Developer Tools, switching to the Network tab, and watching it during a merge: zero outbound data transfers will occur.
Why drag-to-reorder matters
Most online PDF mergers let you upload files but make reordering awkward (text input of file numbers, hidden menus, or no reorder at all). Gizmoop's tool shows each file as a row with a visible position number, an up/down arrow pair, and a drag handle. You can move files into any order with two clicks or one drag. This is critical for legal exhibits, where exhibit order is meaningful, and for academic papers where the cover letter must come first.
File size and count limits
The merger has no hard limit on file count or total size. The practical limit is your device's available memory. A typical desktop with 8 GB of RAM handles merges up to about 500 MB total comfortably. A mid-range laptop handles 200 MB. Mobile browsers usually max out around 50-100 MB total because mobile RAM is more constrained. If you hit memory limits, split your work into batches: merge the first 10 files, save the result, then merge that result with the next batch.
What is preserved during a merge
Text remains text (searchable, copyable, indexable). Images remain images. Embedded fonts stay embedded. Internal links between pages of the same source PDF continue to work. External URL links continue to work. Bookmarks from each source PDF are merged into the result, although they may need cleanup if multiple inputs have identically named bookmarks. Form fields are preserved but may need renaming if multiple input PDFs use the same field name.
What may not survive cleanly: complex JavaScript inside PDFs (interactive forms with custom validation), digital signatures (which invalidate when the PDF is modified), and some specialized annotations (some 3D content, some embedded video). For most office and academic use cases, none of these matter; for niche use cases, test the merged output before relying on it.
How to get the smallest merged file
The merger does not compress as part of the process; it keeps each input file's native compression. If you want a smaller merged file, run it through our PDF Compressor after merging. Image-heavy PDFs typically shrink 30-60 percent during compression; text-heavy PDFs already compress well in their original format and may only shrink 5-15 percent.
If your inputs include duplicate resources (the same logo image embedded in every source PDF), the merged file will include the logo as many times as it appears across inputs. Some advanced PDF tools deduplicate identical objects across merges, but pdf-lib does not. For maximum size efficiency on heavy merges, compress after merging.
Privacy and security
Gizmoop has no servers involved in the merge. We cannot see your PDFs because they never reach our infrastructure. We have no logs of your file names, file contents, or operations. We do not require an account, so there is no profile we could associate with your activity. This is the strongest privacy guarantee any free online PDF tool can offer.
For comparison: iLovePDF's privacy policy states files are deleted within 2 hours. SmallPDF deletes within 1 hour. Both encrypt in transit. Both are reputable companies. Yet for documents you would not email to a stranger (financial records, medical files, legal exhibits, signed contracts), having no upload at all is the safer choice. Gizmoop provides that safer choice without compromising functionality.
Comparison with desktop software
Desktop tools like Adobe Acrobat Pro DC ($14.99/month), Foxit PhantomPDF, and PDFelement all support merging with similar privacy (everything stays on your device). They cost money but offer more features (OCR, advanced editing, e-signatures, batch automation). For occasional merging, Gizmoop's browser tool is free, fast, and just as private. For daily heavy-duty PDF work involving editing, OCR, and forms, a desktop tool is still worth the subscription.
Mobile use
The merger works on iOS Safari 15+ and Android Chrome. Mobile usage is convenient for quick merges of small files (combining receipt photos, merging a few short PDFs received via WhatsApp or email). For large merges or heavy work, mobile is constrained by lower RAM and slower CPUs. If a mobile merge hangs, retry on a laptop or split into smaller batches.
Browser compatibility
The merger uses modern JavaScript and Canvas APIs supported by Chrome 88+, Firefox 89+, Safari 15+, and Edge 88+. Internet Explorer is not supported (Microsoft retired it in 2022). For older browsers, the tool may fail to load or fail during merging. Update your browser or use a different one if you encounter problems.
Where merging fits in a PDF workflow
Merging is usually a finishing step: you collect PDFs from various sources, get them into the right order, and merge them into one deliverable. Common steps before merging: rotate any pages that came in sideways (use our Rotate PDF tool), delete unwanted pages (Delete PDF Pages), and rename files for consistency. Common steps after merging: add page numbers (Add Page Numbers PDF), apply a watermark (Watermark PDF), compress for email delivery (Compress PDF), or password-protect for secure sharing (Protect PDF). All of these tools are also browser-based and privacy-first on Gizmoop.
Frequently asked questions
If you don't find your question here, ask us directly.
Drop your PDFs into the tool above, drag them into the order you want, and click Merge. The combined PDF downloads instantly. Everything happens in your browser, so nothing is uploaded to a server. You can merge any number of PDFs of any size, limited only by your device's memory.
No. Unlike iLovePDF (25-file free cap) and SmallPDF (5 MB total file size free), Gizmoop has no limits on file count or total size. Practical browser memory usually handles 50+ files or 500 MB combined comfortably on a desktop, less on mobile.
No, never. The merger uses the pdf-lib library running entirely in your browser. You can verify this in your browser's developer tools network tab: no upload requests are made. This is the same privacy model TinyPNG uses for image compression and is one of the reasons people choose Gizmoop for confidential documents (contracts, tax records, medical files).
Bookmarks and links are preserved when present in the source PDFs. Form fields are kept but may need manual renaming if multiple input PDFs use the same field names. For PDFs with complex JavaScript or interactive features, test the merged output before relying on it in production.
Yes. Drag any item up or down in the list to change its order, or use the up/down arrow buttons. The position number (1, 2, 3...) on the left shows the final merge order. You can also remove individual files with the × button.
Encrypted PDFs need to be unlocked first. Use the Unlock PDF tool to remove the password (you must know the password), then drop the unlocked PDFs into the merger. The merger can read encrypted PDFs that allow content copying, but most password-protected ones disable that permission.
Most of the time, the merged file is similar in size to the sum of inputs. It can be slightly larger because of duplicated resources (fonts, images appearing in multiple source files) that the merger keeps separate for safety. To reduce the merged size afterward, run it through our PDF Compressor.
Yes. Scanned PDFs are technically PDFs that contain only images of pages. The merger handles them the same way as text-based PDFs. The result file will be image-based; if you need searchable text, run the merged PDF through an OCR tool afterward.
Yes, the tool works in any modern mobile browser (Safari iOS 15+, Chrome Android). Mobile browsers have lower memory limits than desktops, so very large merges (10+ files or 100+ MB total) may slow down. For huge merges, use a laptop or desktop.
There is no hard limit imposed by the tool. The practical limit is your device's available memory. As a rough guide: phones handle up to about 50 MB total comfortably, mid-range laptops handle 200-500 MB, and modern desktops handle 1 GB+. If you see a freeze or crash, try splitting into smaller batches.
Yes. PDF files embed their own fonts and rendering instructions, so a merge preserves the exact appearance of each input file. The merger does not re-render or re-encode anything; pages from source A look identical in the output, and pages from source B look identical too.
iLovePDF and SmallPDF process files on their servers (with 2-hour deletion policies). Gizmoop processes everything in your browser, so there is no upload at all. We have no daily task limits, no file count caps, and no Pro-tier paywalls. The trade-off: Gizmoop runs slower for very large files because your device does the work, while their cloud has more compute.
Yes. The merged file is a standard PDF (version 1.7 by default) and remains searchable, printable, and indexable like any other PDF. Text from text-based source PDFs remains text in the merger's output, so search engines and screen readers can read it normally.
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