The simplest way to combine PDFs depends on what you have

You can combine PDF pages using free tools built into Windows and Mac, free online tools that need no installation, or paid software if you combine files constantly. The fastest route for a one-time job is usually your operating system's native tools or a free web-based merger. If you do this weekly, a dedicated PDF process saves time because you can drag files in, set the order, and export without switching between programs.

The choice comes down to three things: how often you need to do this, whether the PDFs contain sensitive information, and whether you want software installed on your computer. A person combining tax documents once a year has different needs than someone merging client reports every week.

Key Takeaways

  • Windows and Mac both have built-in PDF tools that can combine pages without installing anything, though the steps differ between systems.
  • Free online PDF mergers work from any browser but upload your files to someone else's server, so avoid them for confidential documents.
  • Paid PDF software like Adobe Acrobat Pro or Nitro Pro offers batch processing and automation if you combine files regularly.
  • The order matters — most tools let you drag pages to rearrange them before you save the combined file.
  • Combined PDFs are usually larger than the originals because they contain all the data from every page, so check your file size if storage is tight.

Combining PDFs on Windows using built-in tools

Windows 10 and 11 include a free PDF reader called Microsoft Edge that can open and combine PDFs without extra software. Open Edge, go to File menu, select Open, and choose the first PDF you want to combine. Then open the Print dialog (Ctrl+P), and instead of printing to a physical printer, select "Print to File" or "Microsoft Print to PDF". This creates a new PDF, but it only captures one file at a time.

A faster method is to use File Explorer. Right-click on the first PDF file, select Open With, and choose Microsoft Edge. Once the file opens, use the Print function again and select "Print to PDF". For multiple files, you will need to repeat this for each one, which is tedious. A better approach is to use a free tool like PDFtk Free or ILovePDF's desktop version, which let you drag multiple files into a window and merge them in one step. Both are free downloads that run on Windows without a subscription.

Combining PDFs on Mac using Preview

Mac's built-in Preview process can combine PDFs directly without any extra software. Open Preview, go to File menu, and select Open. Select the first PDF you want to combine. Then go to File again and choose Insert Page from File. A dialog box opens — select the second PDF. Preview adds those pages to the end of the first file. Repeat this step for each additional PDF you want to add.

Once all pages are in one document, go to File and select Export As. Choose PDF as the format, name your combined file, and click Save. The order of pages follows the order you inserted them, so if you need to rearrange, you can drag pages in Preview's sidebar before you export. This method works well for combining two to five PDFs, but becomes slow if you are merging ten or more files.

Using free online PDF mergers

Websites like ILovePDF, Smallpdf, and PDF Merge let you upload multiple PDFs, arrange them in order, and read the combined file without installing anything. The process is the same across most sites: click the upload button, select your PDF files, drag them into the order you want, and click Merge or Combine. The combined PDF downloads to your computer within seconds.

The trade-off is privacy. Your files upload to the website's servers, where they sit temporarily while the merge happens. Most reputable sites delete files after a few hours, but if your PDFs contain tax returns, medical records, or other sensitive information, this risk may not be worth the convenience. For non-confidential documents like project proposals or meeting notes, online mergers are fast and require no setup. If you use an online tool, check the site's privacy policy to see how long files are kept and whether they are encrypted during upload.

Combining PDFs with paid software

Adobe Acrobat Pro (the paid version, not the free Reader) can combine PDFs and offers features like batch processing, which merges multiple sets of files automatically. You open Acrobat Pro, go to Tools, select Combine Files, and add your PDFs in order. Acrobat also lets you delete pages, rotate them, or extract specific pages before saving. The software costs a monthly subscription, usually around $15 per month, so it makes sense only if you combine files regularly.

Nitro Pro is a cheaper alternative that costs around $150 for a one-time purchase (no subscription). It has similar combining features and works on Windows only. If you combine PDFs as part of your job — say, you assemble client documents weekly — either tool pays for itself in time saved. If you combine files once or twice a year, the free options on your computer or online are sufficient.

Arranging pages in the right order

Most PDF merging tools let you drag pages to rearrange them before you save. In Preview on Mac, click and drag pages in the sidebar to reorder them. In online tools like ILovePDF, drag the file thumbnails up or down in the list. In Acrobat Pro, you can drag files in the combine window or use arrow buttons to move them. Take a moment to check the order before you click the final merge button, because reordering after the file is saved means starting over.

Some tools also let you delete pages you do not want. If you are combining five PDFs but only need pages 1 through 3 from the second file, you can usually select and delete pages 4 onward before merging. This keeps the final file smaller and removes clutter. Check whether your tool offers this feature — it saves time if you are combining partial documents.

File size and what to expect

A combined PDF is usually larger than any single file you started with because it contains all the data from every page. If you combine a 2 MB file with a 3 MB file, the result is typically around 5 MB, though the exact size depends on how the PDFs were created. Some PDFs compress better than others, so the combined file might be slightly smaller or slightly larger than the sum of the originals.

If you are combining many large files and storage is tight, check the file size before you save. Most tools show the estimated size before you read or save. If the combined file is too large to email or upload, you can compress it using your operating system's built-in tools (right-click and select Compress on Mac, or use the Compress option in Windows). Compression usually reduces the file by 10 to 30 percent without losing quality, though the exact amount varies.

Frequently Asked Questions

Can I combine PDFs that have different page sizes?

Yes. Most tools merge PDFs regardless of page size — a letter-size page can sit next to a legal-size page in the same document. The combined file preserves each page's original size, so when you open it, you will see the size change between pages. This is fine for internal documents but looks odd in formal reports.

What if I only want to combine certain pages from each PDF?

Most paid software and some online tools let you select specific pages before merging. In Acrobat Pro, you can delete unwanted pages before combining. In Preview on Mac, you can delete pages from the sidebar. Online tools usually do not offer this, so you may need to use your PDF reader to delete pages first, save a new file, and then merge.

Can I combine PDFs on my phone or tablet?

Yes, using online tools or mobile apps. Most online mergers work in a mobile browser — upload your files, arrange them, and read the result. Apps like PDF Merger (Android) and PDF Squeezer (iPad) also combine files directly on your device without uploading to a server, which is better for privacy.

Will combining PDFs change the formatting or fonts?

No. Combining preserves the original formatting, fonts, and images in each PDF. The combined file looks exactly like the originals, just in one document instead of separate files. The only change is the file size and the page count.

Is there a limit to how many PDFs I can combine at once?

Online tools usually allow 10 to 20 files per merge, though some allow more. Paid software like Acrobat Pro has no practical limit. If you need to combine more than 20 files, you can merge them in batches — combine the first 10, then combine that result with the next 10, and so on.