slimdocs

Guides · Updated 2026-06-07 · 4 min read

How to merge and split PDF files

Combine several PDFs into one, or pull specific pages out of a document — with page-range syntax explained and tips to avoid bloated output.

Two of the most common PDF tasks are the opposite of each other: merging several files into one document, and splitting one document into separate pieces. Both are quick, and both have a couple of details worth knowing.

Merging PDFs

Merging combines multiple PDFs into a single file, in the order you choose. It's the right tool when you need to bundle, say, a cover letter, a résumé, and a portfolio into one document to upload, or to assemble scanned receipts into a single expense report.

One thing to watch: a naive merge can produce a file larger than the sum of its parts. That happens when the source files share the same fonts or images — a basic merge copies those resources once per file instead of recognizing the duplicates. slimdocs runs a consolidation pass after merging that removes duplicated images and fonts, so the combined file stays as small as possible.

  1. Open slimdocs and choose Merge PDF.
  2. Add two or more PDFs.
  3. Merge and download the single combined file.

Splitting PDFs

Splitting extracts pages from a PDF. You might need a single chapter from a long report, or want to separate a scanned batch into individual documents. slimdocs lets you either split every page into its own file or pull out specific ranges.

Page-range syntax

When you want specific pages, the range field accepts a simple, flexible format:

The result comes back as a ZIP when there's more than one output file, so everything stays neatly together.

A note on privacy

Both tools process your files entirely in memory. Nothing is written to disk, and the original and result are discarded as soon as your download finishes — useful peace of mind when you're combining sensitive documents like contracts or financial records.

Try it now — free

No sign-up. Files are processed in memory and never stored.

Open slimdocs

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