The simplest way to merge PDFs depends on what you have on hand

You can merge PDFs using built-in tools on Windows and Mac, free online services, or dedicated software — and which one works best depends on how many files you're combining, whether they contain sensitive information, and whether you need to do this regularly.

If you're merging a few PDFs with no sensitive data, an online tool like ILovePDF or Smallpdf takes two minutes and requires no installation. If you're on a Mac, Preview (the app that opens when you double-click a PDF) can combine files directly. On Windows, you can use Microsoft Edge or a free program like PDFtk. For regular merging of confidential documents, a desktop tool you control yourself is safer than uploading to a web service.

Key Takeaways

  • Mac users can drag PDFs into Preview and export them as a single file without installing anything.
  • Windows users can open PDFs in Microsoft Edge, print them to a PDF printer, and select multiple files to combine.
  • Online tools like ILovePDF work on any device but upload your files to someone else's server, so avoid them for confidential documents.
  • If you merge PDFs regularly, a desktop tool like PDFtk or Adobe Acrobat gives you more control and keeps files on your computer.
  • The order matters — most tools let you drag files to rearrange them before merging, so check the preview before you finish.

Merging PDFs on a Mac using Preview

Preview is the fastest method on Mac because it's already installed and requires no extra steps. Open Preview, go to File > Open, and select the first PDF you want to merge. Then go to Edit > Insert > Page from File, choose the second PDF, and repeat for each additional file. The pages from each PDF appear in the order you added them.

Once all files are combined, go to File > Export As, choose PDF from the format dropdown, name your file, and save it. You can rearrange pages before exporting by clicking View > Thumbnails, which shows all pages as small images on the left side — drag them to reorder. This method keeps everything on your computer and takes about a minute for three or four files.

Merging PDFs on Windows using Microsoft Edge or a free tool

Microsoft Edge, which comes with Windows 10 and 11, can combine PDFs by printing them. Open the first PDF in Edge, press Ctrl+P to open Print, and change the printer to "Print to PDF" or "Microsoft Print to PDF." Before you click Print, look for an option that says "Print all pages" or similar — some versions let you select multiple files at once from the file picker. Print the first PDF to a temporary location, then repeat for each additional file.

This method is clunky because you end up with separate files that you then need to combine. A better free option is PDFtk, a command-line tool that works on Windows, Mac, and Linux. read it from pdftk.com, install it, then open Command Prompt and type: pdftk file1.pdf file2.pdf file3.pdf cat output merged.pdf — replacing the filenames with your actual PDF names. This creates a new file called merged.pdf in the same folder. If you're uncomfortable with the command line, PDFtk also has a graphical interface called PDFtk Free GUI that you can read separately.

Using online tools when you don't have the right software

ILovePDF, Smallpdf, and PDF Merge are web-based tools that work on any device — phone, tablet, or computer — without installation. Go to the website, click the button to select files, choose all the PDFs you want to merge, arrange them in order if needed, and click Merge. The site processes them and gives you a read link within seconds.

The trade-off is that your files travel to someone else's server. Most of these services say they delete files after a few hours, but you're trusting their word. Never use an online tool for documents that contain passwords, financial information, medical records, or anything else you wouldn't want a stranger to see. For everyday documents like receipts, invoices, or printed articles, online tools are fast and fine. If you use the same tool regularly, check their privacy policy to see how long they keep files and whether they use them for any other purpose.

When to use paid desktop software

Adobe Acrobat (the paid version, not the free Reader) can merge PDFs and also edit them — change text, add signatures, rearrange pages, or remove sensitive information. It costs about $180 per year as a standalone product or comes with Creative Cloud subscriptions. If you only need to merge files occasionally, this is overkill. But if you regularly work with PDFs and need to edit them, add comments, or fill forms, Acrobat is the standard tool and worth the cost.

Cheaper alternatives include PDFtk Pro (a paid version with a graphical interface), Nitro PDF, or Foxit PhantomPDF. These range from $50 to $150 one-time or per year. For most people, the free options above are enough — you only need paid software if you're doing this as part of your job or need features beyond basic merging.

Checking your merged PDF before you send it

After merging, open the new file and flip through the first few pages and the last few pages to make sure they're in the right order and nothing got cut off. Some tools occasionally drop a page or scramble the order, especially if the original PDFs had unusual formatting. If something looks wrong, go back and try again — most tools let you redo the merge quickly.

If you're sending the merged PDF to someone else, check the file size. A merged PDF should be roughly the sum of the original files — if it's much larger, the tool may have recompressed the pages and lost quality. If it's much smaller, pages may have been removed. For most purposes this doesn't matter, but if you're merging high-resolution scans or images, open the file in Preview or Adobe Reader and zoom in to make sure text and images are still readable.

Organizing files before you merge them

Before you start merging, put all the PDFs you want to combine in a single folder and name them in the order you want them to appear — for example, 01-cover.pdf, 02-chapter1.pdf, 03-chapter2.pdf. This makes it easier to select them in the right order and harder to accidentally include the wrong file. If you're merging many files, this step saves time and prevents mistakes.

Most merging tools show you a preview or let you drag files to rearrange them, so you can fix the order even if you selected them wrong. But starting organized means you're less likely to need to redo it. If you merge PDFs regularly, create a folder on your desktop called "PDFs to Merge" and keep your source files there until the job is done.

Frequently Asked Questions

Can I merge PDFs on my phone or tablet?

Yes, using an online tool like ILovePDF or Smallpdf. Open the website in your phone's browser, tap the button to select files, choose the PDFs from your phone's storage, arrange them, and merge. The result downloads to your phone. For iPhone, you can also use the built-in Files app to combine PDFs, though the process is less straightforward than on a computer.

What if the PDFs are different sizes or orientations?

Most merging tools combine them as-is, so you'll end up with a file that has some pages in portrait and some in landscape, or pages of different sizes. This usually looks fine when you open it, but if you need all pages the same size, you'll need to resize them first using a tool like Adobe Acrobat or an online converter.

Can I merge PDFs and remove blank pages at the same time?

Not with basic merging tools — you'd need to remove blank pages first using a PDF editor, or do it after merging. Adobe Acrobat can do both in one step, but for free tools you'll need to edit the PDFs separately before combining them.

Is it safe to upload PDFs to an online merging tool?

It depends on what's in them. For public documents or things you don't mind others seeing, online tools are safe and convenient. For anything confidential — bank statements, medical records, passwords, or personal information — use a tool that runs on your computer instead, like Preview on Mac or PDFtk on Windows.

Why is my merged PDF so much larger than the originals?

Some merging tools recompress the PDFs during the process, which can increase file size if the originals were already compressed. Others embed fonts or metadata that add size. If the file is much larger than expected, try a different tool or check whether the original PDFs were already optimized for file size.