# PDF Merge, Split & Reorder

> Merge PDFs, split by page count or ranges, and reorder, remove, rotate or duplicate pages. Combines several PDFs into one in the order you choose, splits a PDF every N pages or by page ranges (download as a ZIP), and rearranges pages with a simple page syntax such as "1-3,5,8-end", "odd" or "reverse". Shows page counts before and after and a preview of the first page.

Part of usefulweb.site (https://usefulweb.site/). Results are deterministic calculations from the inputs and the listed assumptions; the API returns exactly what the web page shows.

## Use it
- Human interface: https://pdfmergesplitreorder.usefulweb.site/ (interactive tool at https://pdfmergesplitreorder.usefulweb.site/tool)
- JSON API: POST https://pdfmergesplitreorder.usefulweb.site/api/v1/calculate with a JSON object of inputs (schema: https://pdfmergesplitreorder.usefulweb.site/api/v1/tool)
- OpenAPI: https://pdfmergesplitreorder.usefulweb.site/openapi.json
- MCP (Streamable HTTP): https://pdfmergesplitreorder.usefulweb.site/mcp - tool `pdf_merge_split_reorder`

## Inputs
- mode (select): What to do
- file (file, required): PDF - Max 100 MB in total. Processed on our server and deleted; results can be downloaded for about 2 hours.
- file2 (file): PDF 2 (merge only) - Optional additional PDF for merging.
- file3 (file): PDF 3 (merge only) - Optional additional PDF for merging.
- file4 (file): PDF 4 (merge only) - Optional additional PDF for merging.
- file5 (file): PDF 5 (merge only) - Optional additional PDF for merging.
- zip (file): ZIP with more PDFs (merge only) - Optional: up to 25 PDFs in total, added after the single files in file-name order.
- order (text): File order (merge) - Numbers of the files in the order to merge, e.g. "2,1,3". Files not listed follow in upload order. Empty = upload order.
- pages (text): Pages - For select/reorder, remove and rotate. Page numbers start at 1. Examples: "1-3,5,8-end", "odd", "even", "reverse", "10-1" (descending), "1-9:odd". Leave empty for all pages. For select/reorder, repeated pages are duplicated.
- everyN (integer): Pages per part (split every N pages)
- ranges (textarea): Ranges (split by ranges) - One part per range, separated by ";" or new lines. Each range uses the page syntax above.
- angle (select): Rotation (clockwise)
- password (text): PDF password (only if the file is protected) - Used only to open the file for this conversion; it is written to a private temporary file, never to a command line, and deleted with the job.

## Method
- Every upload is checked by its content (it must start like a PDF) and by qpdf --check. Encrypted PDFs are opened with the password you give (passed to qpdf in a private file, never on a command line) and written without encryption.
- Merge: qpdf copies all pages of each file, in the chosen order, into the first file. Bookmarks and document metadata come from the first file; form fields of all files are kept.
- Split: each part is a separate PDF built from the selected pages; several parts are packed into one ZIP.
- Select/reorder: the page list is taken literally, so "3,1,2" reorders, "1,1,2" duplicates page 1, and "reverse" reverses. Remove keeps every page not listed. Rotate adds the angle to the current rotation of the listed pages (lossless, no re-rendering).
- Page contents are never re-encoded: text, fonts and images stay exactly as they were. qpdf writes a deterministic file ID, so the same input always gives the same file.

## Limits
- Digital signatures in the input become invalid when pages are changed. Keep your originals.