Combine double-sided scans
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Combine double-sided scans into one PDF

Scanned all the fronts, then turned the stack over and scanned all the backs? This tool interleaves them into the right page order in your browser.

  • Runs in your browser
  • Never uploaded
  • No watermark
or drop files here

Up to 25 MB per file · 2 files at a time on your plan

How it works

  1. Add your scans

    Add two PDFs, one with the fronts and one with the backs, or a single PDF with all the fronts followed by all the backs.

  2. Check the backs setting

    Backs are in reverse order is on by default, which matches turning the whole stack over. Turn it off if your backs run from first to last.

  3. Combine and download

    Press Combine to get one PDF with pages in reading order: front 1, back 1, front 2, back 2, and so on.

Pro

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  • Files up to 200 MB
  • 50 files at once
  • Saved workflows
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About combining double-sided scans

Many office scanners and home printers can only feed one side of the paper. The usual workaround is to scan the stack once for the fronts, turn it over and scan it again for the backs. That leaves the pages in the wrong order: all the fronts first, then all the backs, and the backs usually run backwards because the stack was flipped. This tool takes the two halves and interleaves them so the result reads in the right order. With the backs reversed option on, the last page of the backs file is paired with the first front, which is what you get when you flip the whole pile. If your scanner kept the backs in order, turn the option off. Both halves should have the same number of pages; if a sheet has a blank back, scan the blank side anyway so the counts match, and remove blank pages afterwards with Delete pages. Pages scanned upside down can be fixed with Reorder and rotate.

Limits: one or two PDFs per task, each up to 25 MB with a free account, 200 MB on Pro and 500 MB on Business. Browser tools have no daily task limit.

Before you sign in, files can be up to 25 MB. A free account raises this to 25 MB.

Privacy: this tool runs entirely in your browser; the file never leaves your device. Nothing is uploaded, so we have nothing to store or delete.

How to use the PDF tools: Step-by-step help with every tool, limits and your files.

Combine double-sided scans: frequently asked questions

What does backs in reverse order mean?

When you turn the stack over to scan the backs, the last sheet's back is scanned first. This option undoes that so each back follows its front.

Can I use one PDF instead of two?

Yes. Add one PDF that has all the fronts followed by all the backs, and the tool splits it in half before combining.

The pages came out mismatched. What went wrong?

Usually the halves have different page counts, or the backs setting is the wrong way round. Check both and try again.

How do I remove blank backs afterwards?

Open the combined file in Delete pages and click the blank pages to remove them.

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