Merge PDF
Combine several PDFs into one file, in exactly the order you want.
Join contracts, reports, scans or chapters into a single PDF. Add as many files as you like, arrange them in the order you want, and download one tidy document.
How to merge PDF files
- Choose or drop two or more PDF files.
- Drag the files (or use the arrows) to set their order.
- Click “Merge PDF” and download the combined file.
Frequently asked questions
How many PDFs can I merge at once?
There is no fixed limit. The practical limit is your device’s memory, and dozens of typical documents merge without trouble.
Will merging reduce quality?
No. Pages are copied as they are, so text, images and vector graphics stay exactly the same.
How do I combine PDF files into one?
Add two or more PDFs, drag them into the order you want and click “Merge PDF”. You download a single file with every page of every document.
Can I merge PDFs with different page sizes?
Yes. Pages keep their own size and orientation, so A4 letters, US Letter forms and landscape spreadsheets can go into one file without anything being scaled.
Can I merge only some pages of a file?
Run that file through Extract pages first and merge the result, or use Organize PDF, which lets you drag individual pages between documents.
Why is the merged PDF so large?
Merging doesn’t shrink anything: the result is roughly the size of all the files added together. Run it through Compress PDF if it is too big to email.
Are my files uploaded to a server?
No. ModifyPDF processes files with JavaScript inside your browser. Your documents never leave your device, and nothing is stored after you close the page.
What gets merged
Every page of every file is copied into the new PDF in the order you set, with its text, images, fonts and links unchanged. Pages keep their own size and orientation, so you can combine A4 letters with US Letter forms or landscape spreadsheets without anything being scaled.
Tips
Want only some pages from a file? Run it through Extract pages first, then merge the result. To mix pages from several files in any order, use Organize PDF instead: it lets you drag individual pages between documents.
Common reasons to merge
Sending one attachment instead of five, combining a signed contract with its schedules, assembling scanned receipts for an expense claim, or joining chapters exported separately from a word processor. A single file is easier for the recipient to open, print and archive, and many upload forms accept only one document.
Merging on a Mac or in Acrobat
On a Mac, Preview can combine PDFs by dragging page thumbnails from one document into another’s sidebar. Adobe Acrobat’s Combine Files tool does the same but requires a paid plan. ModifyPDF works the same way in any modern browser on Windows, macOS, Linux, Android or iPhone.
If the merged file is large
Merging never shrinks files: the result is roughly the size of all inputs added together. If it is too big to email, run it through Compress PDF afterwards. Scanned pages usually shrink the most.