PDF Merger and Splitter

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All processing happens in your browser. No files are uploaded to any server.

About the PDF Merger and Splitter

The PDF Merger and Splitter combines multiple PDFs into one or extracts ranges of pages from an existing PDF — entirely in your browser via pdf-lib. Drop multiple files to merge in any order; drop one file and pick page ranges to extract. No uploads, no rate limits. Perfect for combining receipts before submitting expenses, splitting a multi-chapter PDF, or extracting a single page to share without exposing the rest of the document. Files stay on your device.

Updated: May 8, 2026

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How to use the tool

  • Drop one or more PDF files. Each file appears as a row in the file list and as a unified strip of page thumbnails in the grid below.
  • Drag rows to change file order, or drag individual page thumbnails to reorder pages across the entire combined output. Click any page card to toggle selection (blue ring).
  • To merge: with no pages selected, the Download button exports every page in the displayed order as a single PDF.
  • To split: select the pages you want to keep, then click Download — the output contains only the selected pages in selection order, letting you extract a subset or re-arrange pages from one or more sources.
  • Page operations are reorder (DnD) and delete (per page or per file). Files up to 200 MB and 1,000 pages per file are supported.

Common use cases

  • Combining expense receipts before submitting reimbursements — many systems accept a single PDF of receipts; merge instead of attaching 20 individual files.
  • Extracting a chapter from a textbook PDF for sharing with a study group — split a 500-page book into individual chapters.
  • Removing pages with sensitive content — split off and discard the page containing personal information before sharing the rest.
  • Combining scanned documents — split a multi-document scan into individual filing-cabinet entries.
  • Reordering signed contracts — move the signature page to the right position in a multi-party agreement.

Privacy and security

pdf-lib runs entirely in your browser as a bundled JavaScript library. PDF parsing, page extraction, merging, and re-encoding all happen client-side. Sensitive documents — contracts, medical records, financial statements, personal identification scans — never leave your device. URL state is not auto-synced; refreshing the page clears the loaded files. For maximum privacy, disconnect from the network before processing the documents.

Tips and pitfalls

  • Merging encrypted PDFs requires the password. pdf-lib can decrypt user-password PDFs if you supply the password; owner-password-only PDFs (which restrict editing but allow viewing) need handling that the tool does not currently expose.
  • Page numbering surprises. PDF pages are 1-indexed in the UI; behind the scenes pdf-lib uses 0-indexed arrays. The tool surfaces 1-indexed numbers to match the visual page count.
  • File size after merge is the sum of input sizes minus duplicate-resource deduplication. Large image-heavy PDFs combine into very large files quickly; consider compressing before merge if file size matters.
  • Form fields and annotations transfer through merge but may not survive split. If your PDF has fillable form fields, test the output before relying on it for signed documents.
  • Scanned PDFs contain bitmaps, not text. The merge / split operations preserve the bitmaps but offer no OCR; if you need searchable output use a dedicated OCR tool first.

Frequently Asked Questions

How many PDFs can I merge at once?
Practical limit is around 50 files or 200 MB total in modern browsers. Beyond that, merging becomes memory-intensive. For very large merges, work in batches: combine 20 files, then merge the resulting batches.
Are encrypted PDFs supported?
User-password-encrypted PDFs work if you provide the password in the dialog. PDFs with owner-password restrictions (no-edit, no-print flags) can still be merged or split — pdf-lib treats those flags as advisory.
Does merging preserve bookmarks and table of contents?
Bookmarks from the first input PDF are preserved; bookmarks from subsequent inputs are dropped (pdf-lib limitation). Page numbers in the table of contents are remapped to the new merged-document numbering. For complex documents with critical TOCs, verify the output.
Can I rotate individual pages?
Yes. Each page in the merge or split UI has a rotate button (90°, 180°, 270°). Useful for combining mixed-orientation scans where some pages were fed sideways.
What about form fields and digital signatures?
Form fields are preserved through merge but field names may collide if multiple input PDFs use the same names. Digital signatures are invalidated by both merge and split — the cryptographic hash of the document changes. Re-sign the output if signature integrity matters.
How are page ranges specified for split?
Comma-separated ranges: `1, 3-5, 7-9, 12` produces 4 separate PDFs (single page 1, pages 3-5, pages 7-9, single page 12). Ranges can overlap if you want pages in multiple outputs. The 1-indexed format matches the visual page numbers in the UI.
Are the output PDFs the same as the inputs?
The page content (text, images, fonts) is preserved bit-for-bit by pdf-lib. The PDF metadata (creator, modification date) reflects the merge/split operation. Cryptographic hashes of input vs output will differ even when the visible content is identical.
Is my PDF uploaded?
Never. Files are loaded into the browser via the FileReader API, processed by pdf-lib in JavaScript memory, and saved back via the standard download mechanism. The DevTools Network tab shows zero outbound requests during merge or split.