You have five PDF files that need to become one. Maybe it’s a report split across chapters, scanned receipts for an expense claim, or contract pages from different sources. Whatever the reason, merging them should take about 30 seconds – not 30 minutes researching tools.
I tested 11 PDF merging tools over the past two weeks – online and desktop, free and paid – to figure out which ones actually work without hidden limits, surprise watermarks, or signup walls. Here’s what I found.
If you’re also looking for a tool that can edit, annotate, or convert your PDFs after merging, check out our guide to the best free PDF editors – it covers the full picture.
Quick Comparison Table
| Tool | Free Limit | Max File Size | Signup Required? | Auto-Delete | Best For |
|---|---|---|---|---|---|
| ILovePDF | Unlimited merges | 100MB | No | 2 hours | Best overall free option |
| PDF24 | Unlimited, no limits | No limit | No | 1 hour | No restrictions at all |
| Smallpdf | 2 tasks/day | 5GB (pro) | No | 1 hour | Cleanest interface |
| Adobe Acrobat Online | 1-2 free tasks | 100MB | Yes (Adobe ID) | 24 hours | Brand trust |
| Sejda | 3 tasks/hour | 50MB / 200 pages | No | 2 hours | Page-level control |
| PDFsam Basic | Fully free (open source) | No limit | No | N/A (offline) | Privacy-first, offline |
| macOS Preview | Built-in | No limit | No | N/A (offline) | Mac users, zero setup |
Best Online Tools to Combine PDFs
1. ILovePDF – Best Free Option Overall
ILovePDF is what I reach for when I need to merge PDFs quickly. No account needed, no daily task limit for merging, and the interface loads fast even on slow connections.
Upload your files (drag and drop works), rearrange them by dragging thumbnails, hit “Merge PDF.” Done. The merged file downloads automatically. I merged 8 files totaling 47MB and the whole process took about 12 seconds.
The free tier caps individual files at 100MB, which covers most use cases. Uploaded files get deleted from their servers after 2 hours. They also have iOS and Android apps if you need to merge on your phone.
One thing that bugged me – the download page shows ads and upsell banners for their premium plan ($4/month). Not a dealbreaker, but it’s there.
Free limits: 100MB per file, unlimited merges
Platforms: Web, iOS, Android
Verdict: The most practical free merge tool for most people
2. PDF24 – No Limits, Seriously
PDF24 is a German tool that’s genuinely free with no restrictions on merging. No file size cap, no daily task limit, no watermarks. I uploaded a 230MB file just to test it and it processed fine – took about 40 seconds, but it worked.
The interface looks dated compared to Smallpdf or ILovePDF. It’s functional, not pretty. You upload files, drag to reorder, click merge. There’s also a desktop version for Windows that works offline.
Files are deleted from their servers after 1 hour. The company is based in Berlin and processes files on EU servers, which matters if you care about GDPR compliance.
Free limits: None
Platforms: Web, Windows desktop
Verdict: Best choice when you have large files or need to merge many documents
3. Smallpdf – Best Interface
Smallpdf has the most polished UI of any PDF tool I’ve used. Everything feels smooth – the upload animations, the drag-to-reorder, the progress indicators. If you care about design, you’ll appreciate this one.
Here’s the catch: free users get 2 tasks per day. That’s total tasks across all Smallpdf tools (merge, compress, convert, etc.), not just merging. After your second task, you’re locked out until tomorrow.
For $9/month (billed annually), you get unlimited tasks plus extra features like electronic signatures and OCR. Honestly, if you merge PDFs more than a couple times a week, ILovePDF or PDF24 are better free options.
Free limits: 2 tasks/day total
Platforms: Web, iOS, Android, macOS, Windows
Verdict: Beautiful tool, but the free tier is too restrictive for regular use
4. Adobe Acrobat Online
Adobe’s free online merger works, but they make you create an Adobe ID before downloading the result. That’s a deliberate friction point to push you toward Acrobat Pro ($12.99/month).
The tool itself is solid. Fast processing, accurate merging, no quality loss. You can rearrange pages and even pull individual pages from different documents into a custom order. Adobe also keeps your files on their servers for 24 hours – longer than competitors.
I’d use this if you already have an Adobe ID from using other Creative Cloud apps. Otherwise, ILovePDF does the same thing without requiring an account.
Free limits: 1-2 free tasks, then requires subscription
Platforms: Web
Verdict: Good if you’re already in the Adobe ecosystem
5. Sejda – Best for Page-Level Control
Sejda stands out because it lets you pick specific pages from each PDF to include in the merge. Most tools merge entire files – Sejda lets you say “pages 1-3 from file A, pages 7-12 from file B.” That’s genuinely useful when you’re assembling a document from multiple sources.
Free tier allows 3 tasks per hour, files up to 50MB, and documents up to 200 pages. Files are deleted after 2 hours.
The interface isn’t as clean as Smallpdf but it’s more capable. If you need granular control over which pages end up in your merged document, this is the tool.
Free limits: 3 tasks/hour, 50MB, 200 pages
Platforms: Web, desktop (Windows, Mac, Linux)
Verdict: Best for cherry-picking pages across multiple PDFs
Best Desktop Tools (Offline, Private)
6. PDFsam Basic – Best Open Source Option
PDFsam Basic is free, open-source, and runs entirely on your computer. Nothing gets uploaded anywhere. For anyone working with confidential documents – legal contracts, medical records, financial statements – this matters.
It’s a Java app, so it runs on Windows, Mac, and Linux. The merge function is straightforward: add files, set the order, merge. You can also split PDFs, rotate pages, and extract specific page ranges.
The UI is utilitarian. It’s not going to win design awards. But it does the job reliably and has been around since 2006, which speaks to stability. I’ve been using it for about 4 years now and it’s never corrupted a file or produced unexpected output.
There’s a “PDFsam Enhanced” paid version ($69/year) with OCR and editing features, but the free Basic version handles merging perfectly.
Price: Free (open source, GPLv3)
Platforms: Windows, macOS, Linux
Verdict: The go-to for privacy-conscious users and anyone who merges PDFs regularly
7. macOS Preview – Already on Your Mac
If you use a Mac, you don’t need to install anything. Preview – the app that opens PDFs by default – can merge files. Not obvious, though.
Here’s how: open the first PDF in Preview, go to View > Thumbnails (to see the sidebar), then drag additional PDF files into the thumbnail sidebar at the position where you want them inserted. Save. That’s it.
It handles large files well and there are zero restrictions since it’s a native macOS app. The downside is that the merge process isn’t intuitive – Apple never made a “merge” button, you’re basically using the insert functionality as a workaround.
Price: Free (built into macOS)
Platforms: macOS only
Verdict: Perfect for Mac users who merge occasionally and don’t want extra software
How to Choose the Right Tool
Look, the choice depends on two things: how often you merge and how sensitive your documents are.
Occasional merging (once a week or less): ILovePDF. Fast, free, no account needed. Just get it done.
Frequent merging: PDF24 (online, no limits) or PDFsam Basic (offline). Smallpdf’s 2-task daily limit makes it impractical for regular use.
Confidential documents: PDFsam Basic or macOS Preview. Your files never leave your machine. Period.
Need page-level control: Sejda. No other free tool lets you pick individual pages from each source file this easily.
Already paying for Adobe: Just use Acrobat. No point adding another tool.
Step-by-Step: Combining PDFs with ILovePDF (Fastest Method)
Since ILovePDF is what I recommend for most people, here’s the exact process:
- Go to ilovepdf.com and click “Merge PDF”
- Click “Select PDF files” or drag your files onto the page
- Rearrange files by dragging the thumbnails (the order here = the order in the final PDF)
- Click “Merge PDF”
- Click “Download merged PDF” – the file saves to your Downloads folder
Total time for merging 5 files under 10MB each: roughly 15 seconds. I timed it.
Common Issues (and How to Fix Them)
Merged PDF is too large
Merging doesn’t compress anything – it just concatenates. If your source files have high-res images, the merged file can get big. Run it through a PDF compression tool after merging. ILovePDF and PDF24 both offer compression alongside merging.
Pages are in the wrong order
Every tool listed here lets you rearrange before merging. If you already merged and the order is wrong, use Sejda or PDFsam to split the PDF back into individual pages, then re-merge in the correct order.
Merged file has different page sizes
This happens when you combine letter-size and A4 documents, or portrait and landscape pages. The merge tool preserves each page’s original dimensions. If you need uniform sizing, open the merged PDF in a PDF editor and adjust page sizes there.
Password-protected PDFs won’t merge
Most free tools can’t merge encrypted PDFs. You’ll need to remove the password first (assuming you have authorization to do so). PDF24 and Sejda both have separate “Unlock PDF” tools for this. After unlocking, merge as normal.
Privacy and Security Notes
Uploading documents to any online tool carries risk. Here’s what each tool claims about file handling:
| Tool | Files Deleted After | Encryption in Transit | Server Location |
|---|---|---|---|
| ILovePDF | 2 hours | Yes (HTTPS) | EU |
| PDF24 | 1 hour | Yes (HTTPS) | Germany |
| Smallpdf | 1 hour | Yes (HTTPS) | Switzerland |
| Adobe Acrobat | 24 hours | Yes (HTTPS) | US |
| Sejda | 2 hours | Yes (HTTPS) | EU |
For anything genuinely sensitive – legal documents, medical records, financial data – use PDFsam Basic or macOS Preview. Offline tools eliminate the upload risk entirely.
Converting Before Merging
Sometimes you need to merge files that aren’t all PDFs. Maybe you have a mix of Word docs, images, and PDFs. Most online merger tools only accept PDF input, so you’ll need to convert first.
ILovePDF and PDF24 both have separate conversion tools (Word to PDF, JPG to PDF, etc.) that you can use before merging. Or use our PDF to Word converter guide if you need to go the other direction.
A faster approach: if you’re on Windows, “Print to PDF” (Microsoft Print to PDF) converts almost anything to PDF. On Mac, File > Export as PDF does the same. Convert your non-PDF files first, then merge.
FAQ
Is it free to combine PDF files?
Yes. ILovePDF, PDF24, and Sejda all let you merge PDFs free without watermarks or signup. PDF24 has the fewest restrictions – no file size cap, no daily limit. Smallpdf limits free users to 2 tasks per day across all tools.
Can I merge PDF files without installing software?
Yes – ILovePDF, Smallpdf, Adobe Acrobat online, PDF24, and Sejda all work in your browser. Upload files, arrange the order, download the merged result. No software installation required.
Is there a page limit when combining PDFs for free?
PDF24 has no page limit at all. ILovePDF allows files up to 100MB with no page cap. Sejda caps free merges at 200 pages or 50MB. The practical limit for most users is file size, not page count.
What is the safest way to merge PDFs online?
Use tools that auto-delete files quickly – ILovePDF (2 hours) and Smallpdf (1 hour) are reasonable. For truly sensitive documents, skip online tools entirely and use PDFsam Basic or macOS Preview. Your files stay on your computer.
Can I combine PDFs on my phone?
ILovePDF and Smallpdf both have free mobile apps for iOS and Android with merge support. You can also use their web versions in a mobile browser. Adobe Acrobat Reader mobile offers merging but requires a paid subscription ($9.99/month).