Merge PDF — Combine PDFs Online
Combine multiple PDF files into one document.
Drop your PDF files hereTap to select files
Supports PDF, up to 200MB each
What to do next
Related tools
About Merge PDF
Merging PDFs sounds like a trivial operation — and on the surface it is — but the tools that do it badly leave behind a long list of headaches: duplicated fonts that double the output size, broken bookmarks, lost form data, page-number gaps, and the dreaded "this PDF cannot be opened" error from a viewer that does not tolerate sloppy concatenation. Favtoo's Merge PDF tool solves the boring problem properly: it reads each input file with pdf-lib, normalises the page tree, deduplicates shared resources where it is safe to, and writes a single clean output that opens in every PDF viewer including the one built into your browser.
The interface is built around the most common real-world merging task: combine three to fifteen documents into one packet, in a specific order, without losing track of which file goes where. Drag and drop the files in any order, then drag the thumbnails to rearrange. The page count for each source file shows next to its name so you can sanity-check the result before exporting. There is no upload step — every file you add lives in your browser tab’s memory and is gone the moment you close it.
Where this tool earns its keep is the edge cases. Merging a 200-page legal exhibit bundle? It works at full speed because pdf-lib operates on object references rather than re-rendering pages. Mixing scanned PDFs with born-digital exports? Both come through with their original resolution and font embedding intact. Combining files that include outline bookmarks? The bookmarks from each source are preserved and namespaced under the original filename so nothing gets lost. The only thing the tool intentionally does NOT do is merge PDFs whose page sizes are wildly inconsistent into a single uniform layout — by design, each page keeps its original size, because rescaling would visibly degrade scanned documents.
The total combined size limit is 200 MB of input, which comfortably handles tax bundles, course readers, multi-document submissions, and most legal exhibit binders. If you regularly hit that ceiling, run each file through Compress PDF first; in practice most users find that compressing the inputs lets them merge twice as many documents.
How it works
- 1Drop two or more PDFs onto the page. The tool accepts as many files as you can fit under the 200 MB combined input cap.
- 2Drag the file thumbnails to rearrange them into the final order. Page counts show next to each file name for sanity checking.
- 3Optional: remove a file from the queue if you uploaded the wrong one — nothing is committed until you press Merge.
- 4Click Merge. pdf-lib walks each source file, copies its page objects, and writes a single optimised PDF in one pass.
- 5Download the combined PDF. Bookmarks, annotations, and form fields from every source file are preserved.
Common use cases
- Combine a cover letter, CV and references into one application packet
- Stitch together signed contract pages with their amendments and exhibits into a single deliverable
- Bundle a scanned receipt set into one expense report attachment
- Merge separate chapter PDFs from a textbook into one searchable study file
- Join several invoices for the same client into a monthly statement PDF
- Combine architectural drawings, site photos and a written report into one project deliverable
FAQ
How many PDFs can I merge?
You can merge as many PDFs as you like, as long as the total size stays under 200 MB.
Can I reorder the files before merging?
Yes — drag and drop to rearrange the file order before merging.
Will the merged PDF keep bookmarks?
Basic structure is preserved. Complex bookmarks may be simplified during the merge.
Will merging PDFs change the page size or layout of any of my files?
No. Each page keeps its original dimensions, orientation, and content stream byte-for-byte. If you merge a US Letter document with an A4 document, the output PDF will have a mix of US Letter and A4 pages — the tool deliberately does not rescale anything because rescaling would either crop content or produce blurry pages.
Can I merge PDFs that have different fonts or were created by different software?
Yes. Each source PDF brings its own embedded fonts; pdf-lib copies those fonts into the output and registers them under unique resource IDs so there is no conflict. Where two source files happen to embed the same font subset, the tool can sometimes deduplicate to save space, but this never affects how the pages look.
What happens to bookmarks and the table of contents?
Outline bookmarks from each source PDF are preserved in the merged output and grouped under the original filename, so a reader can still jump to "Chapter 3" inside the original file 2 even after merging. The original tables of contents are not auto-merged into a single TOC — that is a separate post-processing step.
Are filled-in form fields preserved?
Yes, AcroForm field values from each source file are copied into the merged PDF. If two source files happen to have form fields with identical names, the tool automatically renames duplicates so each value is preserved instead of being silently overwritten.
How big can the input files be in total?
The combined input limit is 200 MB. That comfortably fits dozens of typical office PDFs. If you are merging scanned documents and hit the limit, run each scan through Compress PDF first — that usually halves their size with no visible loss of quality.
Can I merge PDFs and add page numbers in one step?
Not in a single click — the merge runs first to keep responsibility scopes simple. After downloading the merged PDF, drop it into Add Page Numbers to PDF, which lets you pick start number, position, and font.
Does the merged output remain searchable and copyable?
Yes. Text content, OCR layers, and any embedded XMP metadata from each source PDF carry through to the output. The merged file works with PDF text search, copy-paste and screen-reader navigation exactly like the originals.
Can I merge encrypted or password-protected PDFs?
Encrypted PDFs need to be unlocked first using Remove PDF Password. Once unlocked, merge them as normal, then re-apply protection on the merged file with Protect PDF if needed.