What’s the best free tool to combine multiple PDF files?

General
3

If you don’t want PDFsam (which @kakeru already covered pretty well), here are other solid options that are actually free and not shady:

  1. PDF Arranger (Linux / Windows, some macOS builds)

    • Basically a lightweight, more minimal alternative to PDFsam.
    • You can visually drag pages around, delete them, rotate, then export as a merged PDF.
    • Open source, no watermarks, no limits.
    • If you’re on Linux, it’s often in the distro repo (pdfarranger), so install is trivial.

  2. Using built‑in OS tools only (no extra software, no uploads)

    • Windows (10/11):
      This one’s a bit ugly but avoids extra software.
      • Use a free reader like SumatraPDF or even Edge.
      • “Print” each doc to Microsoft Print to PDF and append using a virtual printer that supports merging, like PDF24’s offline suite.
      • Not as clean as PDFsam/Arranger, but works if you’re super paranoid about installing bigger apps.
    • macOS (better than the Windows print method):
      @kakeru already mentioned Preview, but I’ll add:
      • You can also select multiple PDFs in Finder, right‑click, open with Preview, then rearrange pages across all of them at once.
      • Just remember to “Save” or “Export as PDF” at the end. A lot of people forget and think it didn’t work.

  3. PDF24 Creator (Windows, offline)

    • Old‑school looking, but rock solid and free.
    • Installs locally, all processing is offline.
    • Has a “Merge” function where you drag files in, reorder, and save.
    • No watermarks or page limits in the desktop version.
    • Slight disagreement with the online‑tools paranoia: the online PDF24 tools are actually not awful for non‑sensitive stuff, but for anything private I’d still stick to the desktop app.

  4. Command line options (if you’re even a little techy)
    This is where it gets boring but extremely reliable:

    • qpdf or Ghostscript can merge PDFs in one line.
    • Example with qpdf:
      qpdf --empty --pages file1.pdf file2.pdf file3.pdf -- merged.pdf
    • Great when you need to script or batch this and never want to see another GUI.

To answer the “best free tool” part more directly:

  • If you want easy + GUI + no internet + no BS: PDFsam Basic or PDF Arranger.
  • If you want tiny + scriptable: qpdf.
  • If you don’t want to install anything at all and you’re on macOS: Preview is enough.

Personally I’d skip random “free” web mergers entirely for anything more than a couple of throwaway pages. The watermarks and hidden limits are basically their business model, not a bug.