Free Merge PDF Online
Combine multiple PDF files into one document. Drag to reorder pages. No upload, no account.
Merging PDFs combines multiple documents into a single, portable file. This is useful when you need to bundle a cover letter with attachments, combine scanned pages into one document, consolidate monthly reports into an archive, or assemble a final deliverable from multiple sources. Drag to reorder files before merging, then download the combined PDF — all processed locally in your browser.
Click to add files or drag & drop PDFs here
Add as many PDFs as needed · Drag items to reorderHow it works
Add your PDFs
Two or twenty. Each one is read locally as you add it.
Drag them into order
The list order is the page order in the finished document.
Download one file
All the documents combined, with their pages in sequence.
When Do You Need to Merge PDFs?
Merging PDFs is essential when combining reports, contracts, invoices, or presentations into a single deliverable. Instead of sending multiple attachments, a merged PDF is cleaner and more professional. OneConvert uses pdf-lib to combine files entirely in your browser — no upload, no storage, no privacy risk.
Add as many PDF files as needed, drag them to set the order, and click Merge. The combined PDF downloads immediately. There is no limit on the number of files or total file size beyond your available browser memory.
Why the Merged File Is Rarely the Sum of Its Parts
Merging appends the page trees of several documents into one and renumbers every object so the identifiers stay unique. Page content is copied verbatim — no re-compression, no quality change. What varies is the total size, and it rarely equals the sum of the inputs.
If you merge ten files exported from the same template, each carries its own copy of the same embedded fonts. Those copies are not automatically deduplicated, so the result can be noticeably larger than expected. If instead you merge files that share nothing, the total lands close to the arithmetic sum, minus a little overhead saved by writing a single cross-reference table rather than ten.
Order is decided entirely by the list before you press Merge — drag the entries to change it. Internal links inside each source document keep working, because their targets travel with them. Links and bookmarks pointing across documents do not exist in the sources and are not invented during the merge. If two files contain form fields with identical names, the viewer treats them as one field and typing in one echoes in the other; rename fields before merging if you need them independent.