How to Combine Multiple PDF Files Into One

The fastest way depends on what you already have

You can combine PDFs on Windows using built-in tools, on Mac using Preview, or on any computer using free online tools. The method that works best depends on whether you want to keep the files on your computer, how many PDFs you're combining, and whether you need to rearrange pages or just stack them in order.

If you have just two or three PDFs and they're already in the order you want, the fastest route is usually your operating system's built-in tool — no download needed. If you have many PDFs or need to reorder pages before combining them, a dedicated tool like PDFtk or ILovePDF gives you more control. If you don't want to install anything, an online tool works but means uploading your files to someone else's server.

Key Takeaways

Windows 11 can combine PDFs using Microsoft Edge's print function without installing anything extra.
Mac users can open multiple PDFs in Preview, drag pages between them, and export as a single file.
Free desktop tools like PDFtk or Ghostscript let you combine many PDFs at once and rearrange pages before merging.
Online tools like ILovePDF or SmallPDF work on any computer but require uploading your files to their servers.
The order of your PDFs in the folder or upload window determines the order they appear in the final file.

Combining PDFs on Windows using Microsoft Edge

Microsoft Edge has a built-in print-to-PDF feature that can combine files without any extra software. Open the first PDF in Edge, then use the print dialog to add pages from other PDFs to the same output file.

Open your first PDF in Microsoft Edge. Press Ctrl + P to open the print dialog. Under "Printer," select Print to PDF. In the "Pages" field, you can specify which pages to include — leave it blank to print all pages. Click Save and choose where to save the combined file. Then open the second PDF, repeat the print-to-PDF process, but this time select Print to existing PDF if the option appears, or save it with a different name and use a second method to merge them.

This method works well for two or three PDFs in order, but becomes tedious with many files. If you have more than five PDFs to combine, the desktop tools below are faster.

Combining PDFs on Mac using Preview

Preview, the built-in Mac image and PDF viewer, lets you open multiple PDFs and drag pages between them, then export the result as a single file.

Open Preview and go to File > Open. Select your first PDF and click Open. Then go to File > Open again and select your second PDF — it will open in a new Preview window. In the sidebar of the first Preview window, you should see thumbnails of all pages. Click on the second Preview window and drag its pages into the sidebar of the first window. Repeat for any additional PDFs. Once all pages are in one window, go to File > Export as PDF and save your combined file.

If the sidebar isn't visible, click View > Thumbnails. You can rearrange pages by dragging them in the sidebar before exporting, which is useful if your PDFs aren't in the order you want.

Using free desktop tools for larger batches

PDFtk and Ghostscript are free command-line tools that combine many PDFs quickly and let you rearrange pages. They require typing commands rather than clicking buttons, but they're reliable and work on Windows, Mac, and Linux.

To use PDFtk on Windows, download it from pdftk.com, install it, then open Command Prompt and navigate to the folder containing your PDFs. Type pdftk file1.pdf file2.pdf file3.pdf cat output combined.pdf, replacing the filenames with your actual PDF names. The files will combine in the order you list them. To rearrange pages, you can specify them explicitly: pdftk file1.pdf file2.pdf 1-3 5 cat output combined.pdf would take pages 1–3 and page 5 from file2.pdf.

Ghostscript works similarly but uses the command gswin64c -q -dNOPAUSE -dBATCH -sDEVICE=pdfwrite -sOutputFile=combined.pdf file1.pdf file2.pdf file3.pdf. Both tools are free and don't upload your files anywhere, so they're good choices if your PDFs contain sensitive information.

Using online tools when you don't want to install software

Sites like ILovePDF, SmallPDF, and PDF Merge let you upload multiple PDFs, arrange them, and download the combined file. They're convenient because they work on any computer and require no installation.

Go to ILovePDF.com, click Select PDF files, and choose all the PDFs you want to combine. They'll appear in a list that you can rearrange by dragging. Click Merge PDF and download the result. SmallPDF and PDF Merge work the same way. Most of these services are free for files under a certain size — usually 100 MB to 500 MB per file.

The main drawback is that your PDFs are uploaded to someone else's server. If your files contain private information, medical records, or financial documents, this is a real privacy concern. Most of these sites claim to delete files after an hour, but you're trusting their word. For sensitive documents, use a desktop tool instead.

Rearranging pages before combining

If your PDFs aren't in the order you want, or if you need only certain pages from each file, rearrange them before combining. Preview on Mac and online tools like ILovePDF let you drag pages to reorder them. PDFtk and Ghostscript let you specify which pages to include in the command itself.

With Preview, open all your PDFs, then drag pages from the sidebar of one window into the sidebar of another in whatever order you want. With online tools, upload all files and use the drag-and-drop interface to arrange them. With PDFtk, list pages explicitly: pdftk file1.pdf 1-5 file2.pdf 3 7-9 cat output combined.pdf takes pages 1–5 from file1.pdf and pages 3, 7–9 from file2.pdf.

If you only need a few pages from a large PDF, it's often faster to extract those pages first using Preview or an online tool, then combine the smaller files. This also keeps your final file smaller.

Troubleshooting common problems

If your combined PDF has blank pages, the original PDFs may have had formatting issues. Open each original PDF in your viewer and check that pages display correctly before combining. If pages appear out of order, you didn't rearrange them before combining — use Preview or an online tool to rearrange and try again.

If an online tool won't accept your files, they may be too large or in a format the tool doesn't recognize. Check the file size limit on the tool's website. If a file is corrupted, try opening it in a different PDF viewer first — some viewers can repair minor corruption when opening. If PDFtk or Ghostscript gives an error, make sure you're in the correct folder and that the filenames are spelled exactly right, including the .pdf extension.

If your combined file is much larger than expected, the original PDFs may contain high-resolution images. This is normal and doesn't mean anything went wrong. If file size is a problem, use an online tool's compression option or use a dedicated PDF compression tool afterward.

Frequently Asked Questions

Can I combine PDFs that have different page sizes?

Yes. All methods will combine PDFs of different sizes without error. The pages will appear at their original sizes in the combined file, so you may see some pages larger or smaller than others. If you want uniform sizing, use an online tool that offers a resize option, or resize each PDF individually before combining.

What if I only want certain pages from each PDF?

Preview on Mac and online tools let you delete unwanted pages before combining. With PDFtk, specify which pages to include in the command: pdftk file1.pdf 1-3 file2.pdf 5 7 cat output combined.pdf takes pages 1–3 from file1 and pages 5 and 7 from file2. Extract the pages you need first, then combine the smaller files.

Will combining PDFs change the quality or appearance?

No. Combining PDFs is a straightforward merging process that doesn't re-encode or compress the pages. The combined file will look identical to the originals. Online tools may compress files slightly to reduce size, but desktop tools and built-in OS tools preserve quality exactly.

Is it safe to use online PDF tools with sensitive documents?

Online tools upload your files to their servers, which means trusting that they delete files after processing and don't store or view them. For medical records, financial documents, or other sensitive information, use a desktop tool like PDFtk or Preview instead, which keeps files on your computer.

Can I combine PDFs on my phone or tablet?

On iPad, the built-in Files app and some PDF readers like Adobe Acrobat Reader let you combine PDFs. On Android, apps like PDF Merger or Adobe Acrobat Reader offer this feature. Online tools also work on phones and tablets through a web browser, though uploading large files over mobile data can be slow.

This guide is for general information only and is not medical, financial, legal, or other professional advice. For decisions specific to your situation, consult a qualified professional. See our Editorial Policy.