The fastest way depends on what you already have

The simplest method is to use your operating system's built-in tools or free web-based services. On Windows, you can drag PDFs into Microsoft Edge, right-click, and select "Print to PDF" to combine them. On Mac, Preview lets you open multiple PDFs and drag pages between them. If you prefer not to install software, free websites like ILovePDF, Smallpdf, or PDF Merge let you upload multiple files, arrange them in order, and download the combined result in seconds.

If you work with PDFs regularly, dedicated software like Adobe Acrobat (paid) or free alternatives like PDFtk or Ghostscript give you more control over page order, compression, and metadata. The trade-off is a steeper learning curve and the time to download and install the program.

Key Takeaways

  • Web-based tools like ILovePDF and Smallpdf require no installation and work on any device with a browser.
  • Windows users can combine PDFs by opening them in Microsoft Edge and printing to PDF, while Mac users can use the Preview app.
  • If you combine PDFs often, desktop software like Adobe Acrobat or free tools like PDFtk offer faster workflows and more options.
  • File size matters: combining many large PDFs can create a file too big to email, so check the output size before sharing.

Using free web-based tools

Web-based PDF combiners work on Windows, Mac, Linux, and mobile devices without downloading anything. Go to ILovePDF.com, Smallpdf.com, or PDF Merge (pdfmerge.w69.net). Click the upload button, select the PDFs you want to combine from your computer, and they appear in a list. Drag them into the order you want, then click "Merge" or "Combine". The site processes the files and gives you a download link within seconds.

The main limitation is file size. Most free versions cap uploads at 100 MB to 500 MB total, depending on the site. If your PDFs are large or you have many of them, you may need to split the job into smaller batches or upgrade to a paid plan. Also, check the site's privacy policy — some services delete uploaded files after a few hours, while others may keep them longer.

Combining PDFs on Windows

If you have Microsoft Edge installed (it comes with Windows 10 and 11), you can combine PDFs without any other software. Open the first PDF in Edge, then use File > Open to add the next PDF in a new tab. Open each PDF you want to combine this way. Then go to the first tab, click the three-dot menu, select "Print", and choose "Print to PDF" as the printer. In the print dialog, you can select which pages to include, but this method prints one PDF at a time, so you will need to repeat the process for each file and manually merge the outputs.

A faster Windows option is to use free command-line tools like Ghostscript or PDFtk if you are comfortable with the command line. Download Ghostscript from ghostscript.com, install it, then open Command Prompt and run a command like: gswin64c -sDEVICE=pdfwrite -sOutputFile=combined.pdf file1.pdf file2.pdf file3.pdf. This combines the files in seconds, but requires typing the command correctly and knowing where your PDF files are stored.

Combining PDFs on Mac

The Preview app, which comes with every Mac, can combine PDFs without installing anything. Open Preview, go to File > Open, and select the first PDF. Then go to File > Open Again and select the second PDF — it opens in a new Preview window. In the first window, go to View > Thumbnails to see page thumbnails on the left. Drag the thumbnail from the second window into the first window's thumbnail panel in the order you want. Repeat for each additional PDF.

Once all pages are in the right order, go to File > Export As, choose PDF as the format, name the file, and save it. This method works well for a few PDFs but becomes tedious with many files. For faster combining on Mac, you can also use free web tools or install free software like PDFtk Server.

Using desktop software for regular combining

If you combine PDFs weekly or more often, installing software saves time. Adobe Acrobat (paid subscription, around $15 per month) is the industry standard and offers the most features: you can merge, split, compress, and edit PDFs all in one place. Open Acrobat, go to Tools > Combine Files, select your PDFs, arrange them, and click Combine. The output is ready in seconds.

Free alternatives include PDFtk (pdftk.com), which works on Windows, Mac, and Linux but requires command-line use, and Ghostscript, which is powerful but has a steep learning curve. For a middle ground, some free tools like PDF-XChange Editor (Windows only) offer a graphical interface without a subscription. Download and install the software, then follow the in-app instructions to combine your files.

What to do if the combined file is too large

When you combine many PDFs or files with high-resolution images, the output can exceed email size limits (usually 25 MB). Before sharing, check the file size by right-clicking the combined PDF and selecting Properties (Windows) or Get Info (Mac). If it is too large, compress it using a web tool like Smallpdf's compression feature or by using Ghostscript with compression settings.

Another option is to split the combined PDF back into smaller groups and send them separately, or to upload the file to cloud storage like Google Drive or Dropbox and share a link instead of emailing the file. Some email services also let you send files larger than the standard limit if you use their cloud storage integration.

Frequently Asked Questions

Can I combine PDFs on my phone or tablet?

Yes, web-based tools like ILovePDF and Smallpdf work on mobile browsers. Open the site in Safari or Chrome, upload your PDFs, arrange them, and download the result. Some mobile apps like Adobe Acrobat Reader also offer combining features, though the free versions may have limits on file size or number of files.

Will combining PDFs change the quality or appearance?

Most combining tools preserve the original quality and appearance of each PDF. However, if you compress the file to reduce size, some image quality may be lost. Check the output file before sharing to make sure it looks correct.

Can I remove or reorder pages after combining?

Yes. Most web tools and desktop software let you arrange pages before combining. After combining, you can use Preview (Mac), Adobe Acrobat, or free web tools to delete unwanted pages or reorder them, then export the result as a new PDF.

What if one of my PDFs is password-protected?

You will need to remove the password first. If you know the password, open the PDF in Adobe Acrobat or a similar tool, go to File > Properties, and remove the password protection. Then you can combine it with other files. If you do not know the password, you cannot combine it without removing the protection first.

Is it safe to upload PDFs to web-based combining tools?

Most reputable tools like ILovePDF and Smallpdf use encryption and delete files after a few hours. However, if your PDFs contain sensitive information, using a desktop tool or your computer's built-in features (like Preview or Edge) keeps the files on your device. Check the privacy policy of any web tool before uploading confidential documents.