All essentials

Drop in two or more PDFs and I'll stitch them together.

Free tool

Merge PDF

Merge two or more PDF files into a single document. Drag to reorder before you combine. Files never leave your browser.

Good to know

  • Add as many PDFs as you like — reorder by dragging, or with the arrows on a phone.
  • Page size and orientation of every source page are preserved.
  • Encrypted PDFs must be unlocked before merging.

Your files stay on your machine

This tool runs entirely inside your browser tab. Nothing is uploaded, stored, or sent to a server — close the tab and every trace is gone.

These are the free ones — see the full suite

How big a file can it take?

There is no upload, so there is no upload limit — but the work happens in this tab, which means your browser’s memory is the budget. Nothing here will refuse a file for being large; a big enough one simply gets slow and, eventually, reloads the tab. The figures below are rules of thumb on a desktop browser, not enforced caps. On a phone or tablet, expect a good deal less.

  • Every file you add is held open at once, so it is the combined size that counts — comfortable to roughly 200 MB across all of them.
  • No page previews are drawn here, so page count costs you very little: a 2,000-page volume merges as easily as a short letter.

Password-protected PDFs are declined whatever their size — unlock the file first. If a run does die on a long document, splitting it into volumes and working through them one at a time is the reliable way round it.

Built on open source

The Essentials tools do their work in your browser using these open-source libraries, used under the licenses below. Each remains the copyright of its authors.

  • pdf-libMIT · creates and edits the PDFs you download
  • pdf.jsApache-2.0 · reads your PDF and renders the page previews
  • SheetJS (xlsx)Apache-2.0 · reads Excel workbooks — .xlsx, .xls, .xlsb and .ods
  • hyparquetMIT · reads Apache Parquet files
  • hyparquet-compressorsMIT · the Parquet codecs beyond Snappy — Gzip, Zstd, Brotli, LZ4
  • JSZipMIT · bundles multi-file results into one ZIP
  • LucideISC · the icons throughout these tools
  • ReactMIT · the interface itself
  • Next.jsMIT · builds and serves these pages

pdf.js ships fallback fonts contributed by Foxit Software, redistributed here as part of pdf.js. JSZip is dual-licensed; it is used here under the MIT license.