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

You can combine multiple PDF files into a single document using free tools built into Windows and Mac, or through web-based services that require no installation. The method that works best depends on whether you want to keep the files on your computer, whether you need to rearrange pages, and how many PDFs you're combining at once.

Most people find the fastest route is a free web tool like ILovePDF or Smallpdf — you upload your files, arrange them in order, and read the merged result in seconds. If you prefer not to upload files to the internet, your computer's built-in PDF reader or a free desktop program like PDFtk or Ghostscript will do the job offline, though the steps are less visual and take longer to learn.

Key Takeaways

  • Web-based PDF mergers like ILovePDF and Smallpdf are the fastest option for most people and require no software installation.
  • Windows and Mac both have built-in tools — Preview on Mac and Print to PDF on Windows — that can combine files without uploading to the internet.
  • You can rearrange pages and delete unwanted pages before merging, which is useful when combining documents that have cover sheets or blank pages you don't need.
  • Free desktop programs like PDFtk exist but require command-line knowledge, so they're best for people comfortable typing commands rather than clicking buttons.

Using a web tool to merge PDFs in under two minutes

ILovePDF and Smallpdf both work the same way: you visit their website, select the files you want to combine, arrange them in the order you want, and read the result. Neither requires you to create an account, though both offer paid plans with extra features. For most people, the free version is all you need.

Go to ilovepdf.com or smallpdf.com and look for a button labeled "Merge PDF" or "Combine PDF". Click it, then select "Choose Files" or a similar button and pick the PDFs from your computer. The tool will show thumbnails of each file so you can drag them into the order you want. Once you're satisfied with the order, click "Merge" or "Combine", wait a few seconds, and read the result.

The main drawback is that your files travel to the company's servers while they're being merged. Both ILovePDF and Smallpdf say they delete files after a few hours, but if you work with sensitive documents — medical records, financial statements, legal papers — you may prefer to keep everything on your own computer.

Merging PDFs on Mac using Preview

Mac's built-in Preview app can combine PDFs without any additional software. Open Preview, go to File > Open, and select the first PDF you want to merge. Then go to File > Open Again and select the second PDF — it will open in a new Preview window.

In the first Preview window, go to View > Thumbnails to see a sidebar showing all the pages in that document. Now switch to the second Preview window, select all its pages (Command+A), copy them (Command+C), then switch back to the first window and click at the end of the page list in the sidebar. Paste (Command+V) and the pages from the second document will appear at the end of the first.

If you have more than two PDFs to combine, repeat this process — open the third PDF in a new window, copy all its pages, and paste them into your main document. When you're done, go to File > Save and choose where to store the merged file. Preview will ask whether you want to save as PDF; select that option.

Merging PDFs on Windows using Print to PDF

Windows doesn't have a built-in PDF merger like Preview, but you can combine files by printing them to a single PDF. This method is slower than the Mac approach and doesn't let you rearrange pages easily, but it works without installing anything.

Open the first PDF in your default PDF reader (usually Microsoft Edge or Adobe Reader). Go to File > Print, and in the printer dropdown, select "Print to PDF" or "Microsoft Print to PDF". Choose where to save the file and click Print. The first PDF is now saved.

Open the second PDF, print it to PDF again, but this time save it with a different name. Repeat for each additional PDF. You'll now have multiple single-PDF files. To combine them, use a free web tool like ILovePDF, or install a free desktop program like PDFtk or Ghostscript (both are command-line tools, so they require typing commands rather than clicking buttons).

Rearranging and removing pages before you merge

Most web-based PDF mergers let you delete pages from each file before combining them. This is useful if one of your PDFs has a cover sheet or blank pages you don't want in the final document. When you upload files to ILovePDF or Smallpdf, look for an option to edit each file — you'll see thumbnails of every page, and you can click an X or trash icon to remove pages you don't need.

If you're using Preview on Mac, you can delete pages before merging. Open the PDF, go to View > Thumbnails, right-click any page in the sidebar, and select Delete. Do this for each page you want to remove, then proceed with the merging steps above.

On Windows, you'll need to use a web tool or desktop program to remove pages, since Print to PDF doesn't offer that option. If you're combining many documents and need to remove pages from several of them, a web tool will be faster than printing each one separately.

When to use a desktop program instead

Free desktop programs like PDFtk and Ghostscript can merge PDFs on your computer without uploading anything to the internet. Both are powerful and reliable, but they work through the command line — you type commands rather than clicking buttons — so they're best for people comfortable with that approach.

PDFtk is easier to learn than Ghostscript. After installing it, you open a terminal or command prompt and type a command like: pdftk file1.pdf file2.pdf cat output merged.pdf. This tells PDFtk to take file1.pdf and file2.pdf, concatenate them (cat), and save the result as merged.pdf. If you have many files or need to do this regularly, learning the command saves time compared to uploading files to a web tool each time.

Ghostscript is more complex and is usually used for other PDF tasks like compressing files or converting formats. Unless you already use Ghostscript for something else, PDFtk is the better choice for merging alone.

Choosing between methods based on your situation

Use a web tool (ILovePDF, Smallpdf) if you're combining a few PDFs once or twice and don't mind uploading files to the internet. It's the fastest and requires no learning curve.

Use Preview on Mac if you want everything to stay on your computer and you're comfortable with a few extra steps. It takes longer than a web tool but gives you full control and privacy.

Use Print to PDF on Windows if you have only one or two files and don't need to rearrange pages. For anything more complex, switch to a web tool.

Use PDFtk if you combine PDFs regularly and want to work offline. The command-line approach is slower to learn but faster once you know it, and you can save commands as scripts to repeat the same merge with different files.

Frequently Asked Questions

Can I merge PDFs that have different page sizes?

Yes. All the methods described here will combine PDFs regardless of page size — a letter-size page can sit next to a legal-size page in the same document. The merged file will preserve each page's original size, so you might see different widths when you scroll through the result.

Will merging PDFs reduce the file size or quality?

Web tools and desktop programs don't reduce quality when merging — they straightforward combine the files as-is. The merged file will be roughly the same size as all the original files added together. If you need a smaller file, you can compress it afterward using a separate tool.

What if one of my PDFs is password-protected?

Most web tools and desktop programs cannot merge password-protected PDFs without removing the password first. You'll need to open the protected PDF in your PDF reader, enter the password, and save an unprotected copy before merging. Some PDF readers have an option to save without a password under File > Save As.

Can I merge PDFs on my phone or tablet?

Yes, using a web tool. Open ilovepdf.com or smallpdf.com in your phone's browser, tap "Merge PDF", and select files from your phone's storage. The process is the same as on a computer. Some phones also have PDF apps with built-in merge features — check your device's app store.

How do I undo a merge if I made a mistake?

The merged file is a new file separate from your originals, so your original PDFs are unchanged. If you're unhappy with the result, straightforward delete the merged file and try again. Your original files are still there.