Windows doesn’t ship with a PDF merger. Honestly, it’s one of those gaps that surprises people every time they run into it. You’ve got 5 PDF files from a client, you need them as one document, and suddenly you’re searching for tools.
I spent two weeks testing every free method I could find for merging PDFs on Windows – desktop apps, online tools, command-line utilities, even the hidden Edge browser trick. Some worked perfectly. Others had annoying limits or tried to upsell me on every click. Here’s what actually works in 2026, with specific details on each option so you can pick the right one for your situation. If you want a broader look at PDF tools beyond just merging, check out our best free PDF editors roundup.
Quick Comparison Table
| Tool | Type | File Size Limit | Batch Limit | Keeps Bookmarks | Offline | Best For |
|---|---|---|---|---|---|---|
| PDFsam Basic | Desktop | None | Unlimited | Yes | Yes | Power users, large files |
| PDF24 Creator | Desktop | None | Unlimited | Yes | Yes | All-in-one PDF toolkit |
| ILovePDF | Online | 100 MB | 25 files | No | No | Quick one-off merges |
| Smallpdf | Online | 5 GB (pro) | 2 free/day | No | No | Occasional use |
| Adobe Acrobat Online | Online | 100 MB | 1 free merge | Partial | No | Adobe ecosystem users |
| Microsoft Edge | Built-in | None | Manual | No | Yes | Zero-install emergencies |
| PDFtk Free | CLI | None | Unlimited | Yes | Yes | Developers, automation |
1. PDFsam Basic – Best Overall Free Option
PDFsam Basic is open source and completely free. No ads, no watermarks, no “upgrade to pro” nags during merging. I’ve used it for over a year to combine contracts and financial documents, and it has never corrupted a file or dropped a page.
How to merge PDFs with PDFsam Basic
- Download PDFsam Basic from pdfsam.org (the installer is about 45 MB)
- Open it and click “Merge”
- Drag your PDF files into the window or click “Add” to browse
- Reorder files by dragging them up or down
- Choose your output location and click “Run”
The merge takes about 2 seconds for a 50-page combined document. For a 500-page report I tested, it finished in under 8 seconds.
What I like
- Preserves bookmarks, table of contents, and internal links
- Page range selection – merge only pages 5-12 from one file and all pages from another
- Runs on Java, works on Windows 7 through Windows 11
- No internet connection needed
What I don’t like
- The interface looks dated – functional but not pretty
- Requires Java runtime (the installer bundles it, so no manual setup needed)
- The “Visual” module for rearranging individual pages is paid-only
2. PDF24 Creator – Most Feature-Rich Free Tool
PDF24 Creator does way more than merging. It’s a full PDF toolkit: compress, convert, edit, sign, watermark. All free. The company makes money from their online version’s premium tier, so the desktop app stays genuinely free.
I merged a set of 47 scanned documents (each around 3 MB) and the output was a single 118 MB PDF with all pages intact. Took about 12 seconds.
How to merge PDFs with PDF24 Creator
- Download from pdf24.org (about 30 MB installer)
- Open PDF24 Toolbox and select “Merge PDF”
- Add files through the file picker or drag-and-drop
- Rearrange order as needed
- Hit “Merge” and save the output
What I like
- Integrates into the Windows right-click context menu – select multiple PDFs, right-click, merge
- Includes a virtual printer for converting anything to PDF
- No file count or size limits
- Regular updates (last update was June 2026)
What I don’t like
- The toolbox screen shows 30+ tools at once, which can be overwhelming
- Installer offers to set PDF24 as default PDF handler – easy to skip but watch for it
3. ILovePDF – Best Online Option
When I need to merge 2-3 small PDFs and don’t want to install anything, ILovePDF is where I go. The free tier handles up to 25 files per merge with a 100 MB total limit. That covers most use cases.
How to use it
- Go to ilovepdf.com/merge_pdf
- Upload your files (drag-and-drop works)
- Rearrange the order
- Click “Merge PDF” and download the result
The whole process takes under 30 seconds for small files. Uploaded files are deleted from their servers after 2 hours according to their privacy policy.
What I like
- Clean interface, no clutter
- Works on any browser – Chrome, Firefox, Edge
- Google Drive and Dropbox integration for importing files
What I don’t like
- Free tier limits you to 1 task at a time
- 100 MB file size cap. If your PDFs are larger, you’ll need to compress them first
- Strips bookmarks and internal links during merge
4. Smallpdf – Good for Occasional Use
Smallpdf used to be fully free. Now you get 2 free tasks per day before they ask you to subscribe ($12/month). For merging one or two sets of documents, that’s enough. The interface is probably the most polished of any online PDF tool I’ve tested.
One thing Smallpdf does well: it shows a thumbnail preview of every page before merging, so you can visually confirm the order. Other tools just show file names.
What I like
- Page-level preview and reordering
- Fast upload speeds – their CDN handles large files well
- Desktop app available for Windows (also limited to 2 free tasks/day)
What I don’t like
- 2 free operations per day is restrictive if you work with PDFs regularly
- Pushes the paid plan aggressively after your free tasks are used up
5. Adobe Acrobat Online – One Free Merge
Adobe’s online tool gives you exactly 1 free merge before requiring an account and subscription. After that first use, you’ll need Acrobat Pro ($22.99/month) or Acrobat Standard ($12.99/month).
The merge quality is excellent – no surprise from the company that invented the format. Bookmarks are partially preserved, and the output is well-optimized. But one free operation is barely enough to test the tool, let alone use it regularly.
When it makes sense
If you already pay for Adobe Creative Cloud, Acrobat is included in most plans. In that case, this is your best option. For everyone else, PDFsam Basic does the same job without costing anything.
6. Microsoft Edge Print to PDF – The No-Install Trick
Here’s something most people don’t know: you can merge PDFs using Microsoft Edge without installing anything. It’s a workaround, not a proper merge tool, but it works in a pinch.
How to do it
- Open your first PDF in Microsoft Edge
- Press Ctrl+P to open the print dialog
- Select “Microsoft Print to PDF” as the printer
- Under “Pages,” choose “All”
- Save the file
For multiple files, you’d need to print each to XPS first, combine in XPS Viewer, then print to PDF. Look, it’s clunky. I’m including it because sometimes you’re on a locked-down work computer where you can’t install software, and this is the only option.
The catch
This method flattens everything. Bookmarks, hyperlinks, form fields, annotations – all gone. The output is essentially a printed copy saved as PDF. Fine for simple documents. Terrible for anything interactive.
7. PDFtk Free – For Developers and Power Users
PDFtk (PDF Toolkit) is a command-line tool that’s been around since 2004. If you’re comfortable with the terminal, it’s the fastest way to merge PDFs and can be scripted for automation.
How to merge with PDFtk
pdftk file1.pdf file2.pdf file3.pdf cat output merged.pdfThat’s it. One line. Merges three files into one. You can also specify page ranges:
pdftk A=file1.pdf B=file2.pdf cat A1-5 B output merged.pdfThis takes pages 1-5 from file1.pdf and all pages from file2.pdf.
What I like
- Lightning fast – merged 200 files in 4 seconds during my test
- Perfect for batch operations and scheduled tasks
- Preserves all document metadata, bookmarks, and form fields
- Tiny footprint (under 5 MB)
What I don’t like
- No graphical interface
- The free version (PDFtk Free) lacks some features of PDFtk Pro ($3.99)
- Installation requires adding it to your system PATH manually
Which Method Should You Use?
Here’s my honest recommendation after testing all seven options:
For most people: Install PDFsam Basic. It takes 2 minutes, works offline, handles any file size, and you’ll never hit a limit. If you merge PDFs more than once a month, the install is worth it.
For a quick one-off: ILovePDF. No signup, no install. Upload, merge, download, done. Just don’t use it for confidential documents.
For developers: PDFtk. Write a batch script once, merge hundreds of files with a double-click forever.
For sensitive documents: PDFsam Basic or PDF24 Creator. Both work entirely offline. Your files stay on your machine.
If you’re looking for a tool that does more than just merging – editing text, adding signatures, converting formats – take a look at our best free PDF editors guide. And if your merged file ends up too large for email, here’s how to compress it without losing quality.
Tips for Merging PDFs on Windows
Check the page order before saving. I’ve sent merged documents where the appendix ended up before the introduction. Twice. Both times because I trusted the default file order instead of checking.
Watch the file size. Merging 20 scanned documents can easily produce a 200+ MB file. Most email services cap attachments at 25 MB. Compress after merging if you need to share the file.
Preserve the originals. None of these tools modify your source files, but keep them organized anyway. Label them with numbers (01_intro.pdf, 02_chapter1.pdf) so the sort order matches your intended page order.
Test with a small batch first. If you’re merging 50+ files, try with 3-4 first to make sure the output looks right. It’s easier to catch formatting issues early.
FAQ
Can I merge PDF files on Windows without installing software?
Yes. Online tools like ILovePDF, Smallpdf, and Adobe Acrobat Online let you combine PDFs directly in your browser. You can also use the Microsoft Edge Print to PDF workaround, though it strips bookmarks and links from the output.
Does Windows have a built-in PDF merger?
No. Windows 10 and Windows 11 do not include a native PDF merge tool. The closest built-in option is using Microsoft Edge’s Print to PDF feature, which flattens multiple PDFs into one but removes interactive elements. For proper merging, you need a third-party tool like PDFsam Basic or PDF24 Creator – both completely free.
What is the best free PDF merger for Windows?
PDFsam Basic. It’s open source, has no file size limits, works offline, and preserves bookmarks and document structure. PDF24 Creator is another solid free option with more features but a busier interface. For a wider selection, see our full guide to combining PDFs.
Is it safe to merge PDFs online?
Reputable services like ILovePDF and Smallpdf delete uploaded files within 1-2 hours. But if your PDFs contain sensitive information like contracts, tax forms, or medical records, use a desktop tool instead. PDFsam Basic and PDF24 Creator process everything locally – your files never leave your computer.
Can I merge password-protected PDFs on Windows?
Most tools require you to unlock the PDFs first before merging. PDFsam Basic can merge password-protected files if you enter the password during import. Online tools generally cannot handle encrypted PDFs without unlocking them first.