How to use Merge PDF
- 1
Choose two or more PDFs, or drop them onto the page.
- 2
Drag the cards into the right order. Rotate any file that came out sideways.
- 3
Press Merge PDF and download the combined document.
When merging beats emailing five attachments
Expense reports, rental applications and court filings usually ask for “one PDF, please”. Merging lets you send a single file whose pages are already in the order the reader expects: cover letter first, then the form, then the supporting receipts.
How the order works
Files are joined from left to right (top to bottom on a phone). Every page of the first card comes first, followed by every page of the second card, and so on. If you need to pull single pages out of the middle of a file or interleave pages, merge first and then open the result in Organize PDF, where every page gets its own thumbnail.
What is kept
Page content, page sizes, text that can be selected and searched, and web links on the pages are copied as they are. Bookmarks and interactive form fields from the source files are not carried over — fill in forms before merging, or flatten them by printing to PDF. Mixed page sizes are fine — a US Letter page and an A4 page can sit in the same file.
Privacy
The merge runs inside your browser tab with JavaScript. Your PDFs are read from your disk into memory and written back out as a download; no server ever receives a copy.
Merge PDF: frequently asked questions
How many PDFs can I merge at once?
There is no fixed limit. The practical ceiling is your device memory: a modern laptop handles a few hundred megabytes of PDFs comfortably; phones are happier below about 100 MB in total.
Can I merge password-protected PDFs?
Not directly. Open the file with Unlock PDF first (you will need its password), then merge the unlocked copy.
Will merging reduce the quality of my pages?
No. Pages are copied object by object, so text stays text and images keep their original resolution.
Can I change the order after adding more files?
Yes. New files are added to the end of the list and you can drag any card to a new position before you press Merge PDF.