The fastest way to combine PDFs on Windows
The simplest method is to use Windows built-in Print to PDF feature with your file explorer. Open the first PDF, print it to a new PDF file, then repeat for each additional PDF you want to merge. This works on any Windows 10 or 11 machine without installing anything, though it requires manual steps for each file.
If you merge PDFs regularly, ILovePDF (ilovepdfs.com) or SmallPDF (smallpdf.com) are free web tools that let you upload multiple PDFs at once and read a single merged file in seconds. Both work in your browser on any Windows device. For files you want to keep private or work with offline, PDFtk (a free command-line tool) or LibreOffice Draw (free, desktop software) give you more control without uploading to the internet.
Key Takeaways
- Windows Print to PDF is built in and free, but requires opening each file separately and printing it to create the merged result.
- Web tools like ILovePDF and SmallPDF merge multiple files in one upload and work when ready, though your files travel to their servers.
- LibreOffice Draw is free desktop software that lets you import multiple PDFs into one document without uploading anything.
- PDFtk is a free command-line tool for Windows that merges PDFs quickly if you are comfortable typing commands instead of clicking buttons.
Using Windows Print to PDF for straightforward merges
Open the first PDF file in any PDF reader (Adobe Reader, Microsoft Edge, or Windows Photos all work). Go to File > Print, then select "Print to File" or "Microsoft Print to PDF" as your printer. Choose where to save the file and give it a name like "merged_part1.pdf". Click Print.
Repeat this step for each PDF you want to merge, saving each one with a different name. Once all PDFs are printed to files, open the first one again, go to File > Print, and this time print all the individual PDF files you just created into a single final PDF. This method is slow for large batches but requires no software installation and works on every Windows computer.
Merging PDFs with ILovePDF or SmallPDF online
Go to ilovepdfs.com/merge-pdf or smallpdf.com/merge-pdf in any web browser. Click the upload button and select all the PDFs you want to merge at once (hold Ctrl and click each file to select multiple). Both tools let you drag and drop files directly into the browser window, which is faster than clicking through a file dialog.
Arrange the files in the order you want them combined by dragging them up or down in the list. Click Merge or Combine, wait a few seconds, then read the result. The merged PDF appears as a single file ready to use. Both services keep your files on their servers only long enough to process them, then delete them automatically, though you should avoid uploading sensitive documents if privacy is a concern.
Using LibreOffice Draw to merge PDFs offline
read and install LibreOffice (libreoffice.org) for free. Open LibreOffice Draw, go to File > Open, and select the first PDF you want to merge. The PDF will appear as pages in Draw.
Go to Insert > Page from File and select the second PDF. LibreOffice will add those pages to your document. Repeat this step for each additional PDF. Once all pages are in one document, go to File > Export as PDF and save the merged result. This method keeps everything on your computer and gives you control over page order and layout, though the interface is less intuitive than web tools.
Merging PDFs with PDFtk command line
read PDFtk Server (pdftk.com) for Windows and install it. Open Command Prompt (search "cmd" in the Windows start menu). Navigate to the folder where your PDFs are stored by typing cd C:\Users\YourName\Documents (replace with your actual folder path) and press Enter.
Type the command: pdftk file1.pdf file2.pdf file3.pdf cat output merged.pdf (replace the filenames with your actual PDF names). Press Enter, and PDFtk will merge all three files into a new PDF called merged.pdf in the same folder. This method is fast for merging many files at once, but requires you to type commands instead of clicking buttons. The PDFtk website has documentation for more advanced options like removing pages or reordering them.
Comparing the four methods side by side
| Method | Cost | Speed | Privacy | Best for |
|---|---|---|---|---|
| Windows Print to PDF | Free | Slow (manual per file) | Excellent (offline) | One or two files, no software to install |
| ILovePDF or SmallPDF | Free | Fast (seconds) | Good (files deleted after processing) | Quick merges, multiple files at once |
| LibreOffice Draw | Free | Medium (manual per file) | Excellent (offline) | Offline work, control over page layout |
| PDFtk command line | Free | Very fast (batch processing) | Excellent (offline) | Merging many files repeatedly, automation |
What to do if the merged PDF looks wrong
If pages appear out of order, use the web tools (ILovePDF or SmallPDF) because they show a preview where you can drag pages into the correct sequence before merging. If text is blurry or images are low quality, the original PDFs may have been scanned at low resolution — merging will not improve them, but it will preserve whatever quality the originals had.
If the file size is much larger than expected, the PDFs may contain embedded images or fonts. This is normal and usually not a problem unless the file is over 100 MB. If you need to reduce file size, use SmallPDF's compress tool or PDFtk's compress option before or after merging.
Frequently Asked Questions
Can I merge PDFs that have different page sizes?
Yes. All four methods 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 PDF will preserve each original page's dimensions, so you may see different widths or heights when you scroll through the result.
Will merging PDFs reduce the quality?
No. Merging is a file-combining operation that does not re-compress or alter the content. The merged PDF will have the same text clarity and image quality as the originals. The only exception is if you use a tool that re-encodes the PDF during the process, which the methods listed here do not do.
What is the maximum number of PDFs I can merge at once?
Web tools like ILovePDF and SmallPDF typically allow 20 to 30 files per merge. LibreOffice Draw and PDFtk have no practical limit — you can merge hundreds of files if needed. Windows Print to PDF has no limit either, but the process is slow because you handle each file manually.
Can I merge PDFs that are password protected?
No. You must remove the password from each PDF first using the tool that created it or a dedicated PDF password remover. Once the password is removed, you can merge them using any of these methods. Web tools will usually tell you if a file is password protected when you try to upload it.
Do I need to buy software to merge PDFs on Windows?
No. All four methods described here are completely free. Windows Print to PDF is built in, ILovePDF and SmallPDF are free web tools, LibreOffice is free open-source software, and PDFtk is free command-line software. Paid PDF tools exist, but they are not necessary for basic merging.