Merge PDF
Combine multiple PDFs into one document. Arrange the files in the order you want, check their page counts, then create your merged PDF on this device.
Up to 20 files, 50 MiB each, 120 MiB combined and 1,000 total pages. Encrypted PDFs are not supported.
Choose at least two PDFs. Files stay on this device.
How to use Merge PDF
Choose two or more PDF files. Drag each file into the desired position or use its Move up and Move down buttons. Select Merge PDFs, then download the combined document. Each file’s pages remain in their original order.
How it works and its limits
Pages are copied with pdf-lib 1.17.1, preserving page sizes, orientation, vectors and embedded images rather than converting pages to screenshots. This creates a new document: digital signatures will not carry over as valid signatures, and bookmarks, document-level attachments, interactive form behavior, accessibility tags and other document-level features may not be retained. Review important output before sharing. Password-protected, corrupt and unusually large PDFs are rejected. Processing may require several times the input size in browser memory; use smaller batches on mobile devices.
Frequently asked questions
Are my PDFs uploaded?
No. Files are read and combined in this tab, and the download is generated locally. There is no document upload endpoint.
Can I merge password-protected PDFs?
No. Export an unencrypted copy from a trusted PDF application first, if you are authorized to do so. This tool does not remove PDF passwords or permissions.
Why might the merged file be larger?
The tool copies page content into a new PDF. It does not optimize embedded images or guarantee a smaller file. Repeated resources across different input files may remain separate.
Worked example: cover, report and appendix
Suppose cover.pdf has 1 page, report.pdf has 3 and appendix.pdf has 2. Put them in that order before merging. The expected result has 6 pages: cover on page 1, report on pages 2–4 and appendix on pages 5–6. The displayed list order controls this sequence, not alphabetical filename order.
Use Move up and Move down if dragging is difficult or you are working with a keyboard. Reordering files moves each complete document as a block. It does not move individual pages inside a source PDF. To omit or rearrange pages first, create a selected-page document with Split PDF, then add that output to the merge.
Check these points in the downloaded PDF
- The total page count equals the sum of the inputs you intended to include.
- The last page of each source is followed by the right next document.
- Landscape pages, page sizes, text selection and required graphics still behave as expected.
- Any form fields, signatures, bookmarks or accessibility features you depend on are checked in a suitable PDF reader. Page copying does not guarantee preservation of document-level features.
If a merge does not finish
Each input must be no larger than 50 MiB. The merge accepts 2–20 files, at most 120 MiB of combined input and 1,000 pages in total. A phone with limited free memory may need a smaller batch even below those caps. Close other large tabs or reduce the batch instead of repeatedly selecting the same oversized files.
If one document is rejected, open it in a trusted reader and confirm that it is an unencrypted, working PDF. Changing its filename extension does not repair its contents. Keep source files: merging creates a new document and is neither PDF compression nor malware removal. The page-order guide gives a complete preparation and verification workflow.
Examples and practical checks
Understand the result before using it elsewhere.
- Merge PDFs in the right order and check the resultWorked example · 5 min read
- Explore PDF ToolsCompare tools and their limits
- How we test these toolsMethods, verification and limitations