To merge PDFs for free, add them to one tool, put them in order and save a single file. In Merge PDF, attach two or more PDFs, move them into the order you want and click Merge PDFs. The work happens in your browser, so your files aren’t uploaded anywhere. On a Mac, Preview can merge PDFs too, without installing anything.
How to merge PDFs in your browser
- Open Merge PDF.
- Click Attach PDFs and choose your files, or drop them on the page. You can add more in several goes.
- Check the list. The files will be joined from top to bottom.
- Use the arrow buttons to move a file up or down, and the cross to take one out.
- Click Merge PDFs, then Download merged PDF.
The new file is named after the first file in the list, with “-merged” on the end. Your originals aren’t changed. When it’s done, the tool tells you how many pages the merged file has, and lists anything it couldn’t carry over.
Your files stay on your device
Some online tools upload your files to a server to do the work. Merge PDF doesn’t. It reads and joins the files with code running in your browser, and the merged PDF is made on your own computer or phone. That matters for contracts, medical letters, payslips and anything else you wouldn’t hand to a stranger.
Getting the order right
Files join in the order they appear in the list, and each file’s pages stay in their own order. A few habits help.
- Number the file names first, such as 01-letter.pdf and 02-invoice.pdf. When you choose several files at once, they may not arrive in the order you clicked them, and numbered names make the list easy to check.
- Add files in several goes if that’s easier. Each new file joins the bottom of the list.
- Fix single pages afterwards. To move pages around inside the merged file, use Reorder Pages. To take some out, use Delete Pages.
What carries over to the merged file
Merge PDF copies every page into a new file. The pages look exactly as they did, but some extras that belong to a whole document don’t come with them.
| Part of the PDF | In the merged file |
|---|---|
| Pages, text and images | Kept, unchanged |
| Comments and highlights | Kept on their pages |
| Links to websites | Kept |
| Links to other pages in the same file | Kept when they point straight at a page. Some others stop working |
| Bookmarks | Not carried over |
| Fillable form fields | Not carried over |
| Attachments | Not carried over |
| Title and author | Not carried over, so the merged file starts blank |
| Accessibility tags and page labels | Not carried over |
| Digital signatures | Removed, because a signature can’t survive a merge |
For forms, fill them in before you merge and check that the answers show in the merged file. If a form must stay fillable, send it separately. If you want the merged file to have a title, add one afterwards with Metadata Editor.
Some PDFs also have layers that stay hidden until you switch them on. In the merged file those layers show, and the tool warns you when that happens, so check the result before you send it.
Mixing page sizes
Every page keeps its own size and direction. An A4 letter, a US Letter form and a landscape spreadsheet can sit in one file, each at its own size. Nothing is stretched, shrunk or cropped. Viewers show mixed sizes without trouble, and when you print, the print window’s fit-to-page setting handles the difference. If a scanned page comes out sideways, turn it with Rotate PDF.
Merging large files
Because nothing is uploaded, there’s no upload limit and no waiting for a transfer. The limit is your device’s memory, since every file is read into the browser while it works.
- A merged file is roughly the size of the files added together, sometimes a little smaller. The tool doesn’t compress images, so it won’t shrink a large scan.
- If a big merge fails, or a phone struggles, close other tabs and merge in batches: join half the files, then merge that result with the rest.
- If the result is too big to email, use Split PDF to send it in parts. How to split a PDF explains how.
Other ways to merge PDFs
Preview on a Mac
- Make a copy of the first PDF, because Preview saves changes into the file you open.
- Open the copy in Preview and choose View > Thumbnails.
- Drag the other PDFs from Finder onto the sidebar, dropping each one where it should go.
- Drag thumbnails up or down to fix the order, then press Cmd+S to save.
Finder on a Mac
Select the PDFs in Finder, Control-click one of them and choose Quick Actions > Create PDF. Finder joins them into a new file in the same folder. Give the files numbered names first if the order matters.
Adobe Acrobat and Windows
Adobe Acrobat’s paid version has a Combine Files tool. The free Acrobat Reader can’t merge PDFs. Windows has no built-in way to join PDFs either: Microsoft Print to PDF prints one document at a time.
Common problems
- A file is password-protected. Merge PDF names the file and stops. Remove the password in the program that set it, then add the file again.
- A file won’t open at all. It may be damaged, or not really a PDF. Try opening it in your browser first.
- A page is in the wrong place. Use Reorder Pages on the merged file rather than starting again.
- A signature is no longer valid. That’s expected. Send the signed original alongside the merged file if the signature matters.
Frequently asked questions
How do I combine PDF files into one for free?
Attach them to Merge PDF, arrange them, and click Merge PDFs. It’s free, needs no account, and works in your browser. On a Mac, Preview and Finder’s Create PDF quick action work too.
Can I merge PDFs without uploading them?
Yes. Merge PDF joins the files on your own device, so they never leave it. Preview and Finder on a Mac also work without uploading anything.
Does merging PDFs reduce the quality?
No. Pages are copied as they are, not printed or converted, so text stays sharp and images aren’t compressed.
Are bookmarks kept when you merge PDFs?
Not with Merge PDF. Bookmarks, fillable form fields and attachments are left out, and the tool tells you when a file had them. Most links on the pages are kept.
