Merge Odd and Even PDF Pages
Interleave odd-page and even-page scan PDFs into the original order
About this tool
Interleave two scans from the chosen first side, with optional reversal of the entire even-side scan. When counts differ, all remaining pages from the longer scan are appended. Exactly two PDFs, each with 1–80 pages and up to 20 MiB. At most 160 pages and 40 MiB combined input; one output PDF, up to 160 pages and 100 MiB. Forms, XFA, widgets, signature permissions and portfolios are rejected. Digital signatures do not remain valid; outlines, attachments and cross-page destinations are not rebuilt. Review ordinary annotations after downloading. PDF content is processed locally, with manual downloads after the complete operation succeeds.
Scenario Recipes
Reassemble scans whose back sides were fed in reverse
Goal: Reversal applies to all even pages before alternation or preview truncation. O/E labels always identify the original page index within that scan.
- Load odd/front pages into O and even/back pages into E. Check the actual page counts for both.
- Select reverse-even only when the second scan is in reverse feed order; choose which side comes first.
- Review O1/E8 style source mappings, confirm and download. Check the first, last and any unmatched pages.
Result: New PDFs match the reviewed source-page mapping and are downloaded manually for inspection.
Failure Clinic (Common Pitfalls)
The scans have very different page counts
Cause: A missing scan or incorrect file can produce an alternating prefix followed by a long remainder.
Fix: Check the originals and the mismatch notice before confirming. Appending all remaining pages does not prove the scan set is complete.
Generated files disappear after a change
Cause: Output bytes belong to the source files and settings used to create them.
Fix: Review and generate again after changing options, order, sources, clearing or switching language. Old downloads do not continue.
A form or signed document is rejected
Cause: Forms, XFA, widget annotations, signature permissions and portfolios are rejected. Page copying does not preserve valid digital signatures or rebuild outlines, attachments and cross-page destinations. Ordinary annotations need output review.
Fix: Use an export or flattening workflow that explicitly supports those features, and retain the original document.
Production Snippets
Reassemble scans whose back sides were fed in reverse
text
Odd scan: O1…O8; even scan: E1…E8
Reverse entire even scan; first side O
→ O1,E8,O2,E7,O3,E6,O4,E5,O5,E4,O6,E3,O7,E2,O8,E1
Unequal counts: append every remaining page from the longer input.Frequently Asked Questions
When should I reverse the even scan?
Use it when the back-side scan was fed in reverse order. With eight even pages, the sequence begins E8, E7, E6 before it is interleaved.
What if the page counts differ?
Alternate while both scans have pages, then append every remaining page of the longer scan. Review the mismatch notice because a missing scan can still produce a valid PDF.
What do O1 and E8 mean in the preview?
They mean original page 1 of the O input and original page 8 of the E input. They are source positions, not the printed page numbers or output positions.
What are this tool’s file and page limits?
Exactly two PDFs, each with 1–80 pages and up to 20 MiB. At most 160 pages and 40 MiB combined input; one output PDF, up to 160 pages and 100 MiB.
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