PDF Modern
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Interleave PDFs

Organize

Merge two PDFs by alternating their pages — perfect for re-combining one-sided scans of fronts and backs back into a duplex document.

How to use Interleave PDFs

  1. Open this page in any modern web browser — no download or installation required.
  2. Click Add file or drag and drop your PDF onto the drop zone.
  3. Adjust the available settings to fit your needs.
  4. Click the action button and save the processed file — the result is ready instantly.
PDF #1 (will provide odd pages)
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Drop files here or click to browse
PDF #2 (will provide even pages)
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Drop files here or click to browse
🔒 100% Private

Files never leave your browser. No upload to any server.

⚡ Instant

Processing runs locally on your device. No queues, no waiting.

🆓 Free Forever

No signup, no watermarks, no limits. Use as many times as you like.

Why use Interleave PDFs on PDF Modern?

PDF Modern’s interleave pdfs tool processes your file entirely within your web browser using modern WebAssembly technology. Unlike traditional online PDF services that require uploading your documents to remote servers, your files never leave your device — ensuring complete privacy and security. Processing happens at the full speed of your CPU, not limited by upload or download bandwidth, so even large files are handled in seconds. There are no file-size restrictions, no daily usage caps, no watermarks on output, and no account creation needed. It is a fully free, open tool built for everyday document workflows at home, school or the office.

Frequently asked questions

What if the PDFs have different page counts?

Once one file runs out of pages, the remaining pages of the other are appended at the end.

Can I reverse the second PDF first?

Yes — toggle "Reverse second PDF" if your back-side scan came out in the wrong order.