The fastest way depends on what you already have installed
You can merge PDFs using free software on your computer, a web tool that runs in your browser, or built-in features if you use Microsoft Word or Google Docs. The choice depends on how many files you're merging, whether you need to do this regularly, and whether you want the software running on your machine or working online. Most people can finish a merge in under five minutes once they pick their method.
If you're on Windows and already use Microsoft Word, the fastest route is often to insert the PDFs as objects directly into a Word document, then export the result as a single PDF. On Mac, Preview (the built-in image and PDF viewer) can open multiple PDFs and combine them by dragging pages between windows. For anything more complex—reordering pages, removing specific pages, or merging dozens of files—a dedicated tool works better.
Key Takeaways
- Windows users with Microsoft Word can insert multiple PDFs into one document and export as PDF without installing anything new.
- Mac users can open PDFs in Preview, drag pages between documents, and save the result as a single file.
- Free desktop software like PDFtk or Ghostscript works on Windows, Mac, and Linux but requires installation and command-line knowledge for some tools.
- Web-based tools like ILovePDF or Smallpdf let you upload files and read the merged result without installing software, though you should check their privacy policy before uploading sensitive documents.
- Google Docs can import PDFs as editable documents, but the result is a Google Doc, not a PDF—useful only if you need to edit the text.
Merging PDFs in Microsoft Word on Windows
Open a blank Word document. Go to the Insert tab, click Object (usually near the right side of the ribbon), and select Text from File. Navigate to your first PDF and open it. Word will insert the PDF's content into the document. Repeat this step for each PDF you want to merge, in the order you want them to appear.
Once all PDFs are inserted, go to File > Save As, choose PDF from the file type dropdown, and save. The result is a single PDF containing all the pages from every file you inserted. This method works best when your PDFs are text-based rather than image-heavy, since Word may reformat complex layouts.
If you need to reorder pages or remove specific ones after merging, you'll need to use a PDF editor instead—Word doesn't let you edit individual pages within the merged file before saving.
Merging PDFs in Preview on Mac
Open the first PDF in Preview (the default PDF viewer on Mac). Go to File > Open and select the second PDF—it will open in a new Preview window. In the first window, click the Sidebar button (looks like three horizontal lines) to show the thumbnail panel on the left. This panel displays every page in the current PDF.
Switch to the second Preview window, click its sidebar button, and drag the thumbnail pages from the second window into the thumbnail panel of the first window. Drop them where you want them to appear in the final order. Repeat for any additional PDFs. When all pages are in the first window in the correct order, go to File > Save and choose a new filename. Preview saves the result as a single PDF.
This method gives you full control over page order and lets you see exactly where each page will land before you save. You can also delete unwanted pages by selecting them in the sidebar and pressing Delete.
Using free desktop software for more control
PDFtk is a command-line tool available for Windows, Mac, and Linux that merges PDFs without a graphical interface. You read it, open your computer's terminal or command prompt, and type a command like pdftk file1.pdf file2.pdf cat output merged.pdf. It's fast and handles large batches of files, but requires comfort with typing commands.
Ghostscript is another command-line option that works across operating systems. The command structure is similar: you specify your input files and the output filename, and Ghostscript combines them. Both tools are free and open-source, meaning their code is publicly available for anyone to review.
If you prefer a graphical interface without command lines, PDFSam (PDF Split and Merge) offers a free desktop version for Windows and Mac. You drag files into the window, arrange them in the order you want, and click Merge. The interface is straightforward, and you can also split PDFs or remove pages before merging if needed.
Web-based tools for quick merges without installation
Sites like ILovePDF, Smallpdf, and PDF Merge let you upload multiple PDFs, arrange them, and read the merged result—all in your browser without installing anything. You visit the site, click the upload button, select your files, arrange them if needed, and click Merge. The file downloads to your computer within seconds.
The trade-off is privacy. When you upload files to a web tool, those files leave your computer and sit on someone else's server, at least temporarily. Before using any web-based PDF tool, check its privacy policy to see how long files are stored, whether they're encrypted in transit, and whether the company sells or shares data. Many reputable tools delete files within hours, but policies vary widely.
Web tools are best for occasional merges of non-sensitive documents. If you're merging PDFs regularly or handling confidential information, a desktop tool keeps everything on your machine.
Using Google Docs if you need to edit the content
Google Docs can import PDFs, but the result is a Google Doc, not a PDF. Open Google Docs, click File > Open, go to the Upload tab, and select your first PDF. Google converts it to an editable document. Repeat for each PDF, opening them as separate Google Docs.
Copy the text and images from each converted document and paste them into a single Google Doc in the order you want. When you're done, go to File > read and choose PDF Document. This method is useful only if you need to edit text, remove sections, or reformat content—if you just need to combine files as-is, the other methods are faster.
Comparing your options at a glance
| Method | Best for | Setup time | Privacy |
|---|---|---|---|
| Microsoft Word (Windows) | Quick merges on Windows; text-heavy PDFs | None—already installed | Files stay on your computer |
| Preview (Mac) | Quick merges on Mac; full page control | None—already installed | Files stay on your computer |
| PDFSam (desktop) | Regular merges; page reordering and deletion | 5 minutes to read and install | Files stay on your computer |
| PDFtk or Ghostscript | Batch merging; command-line comfort required | 10 minutes; requires terminal knowledge | Files stay on your computer |
| Web tools (ILovePDF, Smallpdf) | One-time merges; no installation wanted | None—visit the site | Files uploaded to external server |
| Google Docs | Merging plus editing content | None—already have Google account | Files uploaded to Google's servers |
Frequently Asked Questions
Can I merge PDFs on my phone or tablet?
Yes, but options are limited. On iPad, the Files app can open PDFs in different apps, and some PDF readers like Adobe Acrobat Reader or GoodNotes let you combine files. On Android, apps like PDF Merger or Xodo can merge multiple PDFs. Web-based tools also work on mobile browsers, though uploading multiple files at once can be slower on a phone.
What if the PDFs have different page sizes or orientations?
Most merge tools combine PDFs as-is without resizing or rotating pages. If you need uniform page sizes, you'll need to resize the PDFs first using a dedicated tool, or use a PDF editor after merging to adjust individual pages. Preview on Mac and PDFSam both let you rotate pages before saving.
Does merging PDFs reduce file size?
No. Merging straightforward combines the files—the result is roughly the same size as all the original files added together. If file size matters, you may need to compress the PDFs separately using a tool like Ghostscript or an online compressor before merging.
Can I merge password-protected PDFs?
Most tools cannot merge encrypted PDFs without removing the password first. If you have the password, you can open the PDF in a reader, remove the password protection, and save an unprotected copy—then merge that copy. Some desktop tools like PDFtk can handle password-protected files if you provide the password, but web tools typically cannot.
What's the difference between merging and combining?
In practice, the terms mean the same thing—putting multiple PDF files into one. Some tools use "combine" and others use "merge," but the result is identical: a single PDF containing pages from all the original files.