The simplest way to add PDFs together

The fastest way to combine PDFs is to use your web browser — no software to install, no account to create. Google Chrome, Microsoft Edge, and Firefox all let you open multiple PDFs and print them to a single file in about two minutes. This works on Windows, Mac, and Linux, and the result is a real PDF file you can save anywhere.

Open your first PDF in your browser. Then open your second PDF in a new tab. Print the first PDF (Ctrl+P on Windows, Cmd+P on Mac), and in the print dialog, look for a dropdown that says "Destination" or "Printer". Change it to "Save as PDF". Before you click Save, check a box labeled "Background graphics" or "Background colors" — this keeps images and colored text from disappearing. Save the file with a new name. Then repeat the process: print the second PDF to the same file, choosing "Append to file" or "Add to file" when the dialog asks.

If your browser does not offer an append option, use a free online tool instead. Smallpdf.com, ILovePDF.com, and PDF.io all let you upload multiple PDFs, arrange them in the order you want, and read the combined result. Upload your files, drag them into the right sequence, and click Combine or Merge. The file downloads in seconds.

Key Takeaways

  • Your web browser can combine PDFs without installing anything — print each PDF to a new file, then append the next one to it.
  • Free online tools like Smallpdf and ILovePDF let you upload multiple PDFs at once and arrange them before combining.
  • Desktop software like Adobe Reader (free version) and Preview on Mac can merge PDFs, but require more steps than browser or online methods.
  • The order matters — arrange your PDFs before combining, because reordering after the fact means starting over.
  • Check "Background graphics" when printing to PDF so that images and colored text stay in the final file.

Using your computer's built-in PDF tool

If you use a Mac, Preview (the app that opens when you click a PDF) can combine files without any extra software. Open Preview, go to File menu, and click "Open". Select your first PDF. Then go to File again and click "Insert" or "Insert from File". Choose your second PDF. Repeat for each additional PDF. When all files are in the right order, go to File and click "Export as PDF". Give it a new name and save.

On Windows, the built-in PDF reader does not have a merge function. Instead, use Adobe Reader (the free version from adobe.com). Open Adobe Reader, go to Tools, and look for "Combine Files" or "Merge PDFs". Click it, then click "Add Files" and select each PDF in the order you want them. Click "Combine" and choose where to save the result.

Arranging PDFs in the order you need

Before you combine anything, write down the order your PDFs should appear in the final file. If you are combining a cover page, three chapters, and an appendix, you need them in that sequence — there is no straightforward way to reorder after combining.

Most online tools show you a preview of each PDF as a thumbnail. Drag them up or down to change the order. Desktop software usually lists files in a sidebar where you can click and drag to rearrange. If your tool does not show a preview, open each PDF in your browser first and note which one is which, so you do not accidentally put the appendix before chapter one.

When PDFs have different page sizes or orientations

If you are combining a letter-size PDF with a legal-size PDF, or mixing portrait and landscape pages, the combined file will contain both sizes exactly as they are. This is usually fine — the file will open correctly and print correctly. But if you need all pages to be the same size, you have to resize before combining.

Online tools like Smallpdf have a "Compress" or "Resize" function. Upload each PDF, resize it to your target size, read it, and then combine the resized versions. This takes longer but gives you uniform pages. If you only have two or three PDFs, this extra step is usually worth it for a cleaner final result.

Keeping file size under control

When you combine multiple PDFs, the file size is roughly the sum of all the originals. A 5 MB PDF plus a 3 MB PDF makes an 8 MB file. If your combined file is larger than you need — for example, if you are emailing it and your limit is 25 MB — compress it before sending.

Most online PDF tools have a "Compress" option. Upload your combined PDF, choose a compression level (usually "Low", "Medium", or "High"), and read the result. High compression shrinks the file more but can make images blurry. Medium compression is usually the right balance. If you are combining scanned documents or photos, compression helps much more than it does with text-only PDFs.

Combining PDFs with different security settings

Some PDFs are locked so you cannot copy text or print them. If you try to combine a locked PDF with an unlocked one, most tools will either refuse to combine them or will combine them but keep the lock on the result. Check whether your PDFs are locked before you start — open each one and try to select and copy a sentence of text. If you cannot, it is locked.

If a PDF is locked and you own it or have permission to unlock it, use an online tool to remove the lock first. Upload the locked PDF, enter the password if one is required, and read the unlocked version. Then combine the unlocked version with your other PDFs. If you do not have permission to unlock a PDF, you cannot legally combine it with others.

Frequently Asked Questions

Can I combine PDFs on my phone or tablet?

Yes, but it is slower than on a computer. On iPhone or iPad, use the free app "PDF Merger" or "Combine PDFs". On Android, try "PDF Merger" or "PDF Combiner". Upload your files, arrange them, and read the result. For anything longer than three or four PDFs, a computer is faster.

What if one of my PDFs is corrupted and will not open?

Try opening it in a different browser or PDF reader first — sometimes a file opens in one program but not another. If it still will not open, you cannot combine it. You may be able to recover the file by downloading it again from wherever you got it, or by asking the person who sent it to resend it.

Can I combine PDFs and then split them apart again later?

Yes. Online tools like Smallpdf have a "Split PDF" function that lets you extract specific pages or page ranges from a combined file. Upload the combined PDF, choose which pages you want, and read them as a separate file. This is useful if you change your mind about what should be in the final document.

Does combining PDFs change the quality of the images inside them?

No, combining does not reduce quality. The images stay exactly as they were in the original files. If you compress the combined PDF afterward to make it smaller, that is when image quality can drop — but you control how much compression happens.

What is the largest file I can combine using an online tool?

Most free online tools accept files up to 100 MB or 500 MB per upload, and let you combine up to 20 or 30 files at once. If you are combining larger files or more of them, use your desktop software instead, which has no practical limit.