Collate a double-sided scan into page order

Flip a document so the last page comes first, turn round a single stretch of pages, or weave two scanned halves back together.

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.pdf · up to 300 MB

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How to Reverse pages

1
Add your PDF
Drop in one file or up to twenty. The document is opened by your browser, so nothing is uploaded.
2
Pick reverse all, a range, or interleave
Flip the whole document, type a range like 5-12 to turn round just that stretch, or use interleave to merge a two-pass scan of a double-sided stack.
3
Download the reordered PDF
Save the result straight to your device. When you reversed several documents at once they come back together in one ZIP archive.

One PDF: all the fronts, then the backs

The page opens with “Interleave” under “What to reverse” and “Front” under “Starts with”. The main Reverse pages tool starts at “Whole document”. This page expects one PDF with all fronts first, then the backs in reverse order. On October 22, 2026, our 20-page test file ran fronts 1 to 10, then backs 10 to 1. It came back as Front 1, Back 1, Front 2 and so on to Back 10. Each thumbnail under “Result order” shows its old place, such as “2 · was 20”. “Back” puts each back ahead of its front.

Two files from the scanner: merge them first

If the scanner saved each pass as its own PDF, do not drop both here. Each file is interleaved on its own. Our two ten-page files came back “Ready to download” as pulsarkit-reversed.zip, with no warning. Inside, one ran Front 1, Front 10, Front 2, the other Back 10, Back 1, Back 9. Join them in Merge PDF first, fronts file first, and press “Download PDF”. Back on this page in the same tab, press “Use it”. Sejda's “Alternate & Mix” mixes pages “from 2 or more documents”, its page said on October 22, 2026. This page needs one.

Odd page counts and skipped blank backs

Nineteen pages from ten sheets gave “Needs fixing” and “the document has 19”. If the missing page is the last sheet's blank back, it belongs right after the last front, page 10 here. In Insert blank page, press the “+” after page 10; that tool starts at “After page” 1. Download, come back in the same tab and press “Use it”. A scanner that skips blank pages can also leave an even count. Our 18-page file lacked the blank backs of sheets 4 and 7. Nothing warned, and from sheet 4 on, fronts got the wrong backs. The last two thumbnails were both fronts, so check there. Blanks after pages 13 and 15, where those backs belonged, fixed it.

File size, speed and what the file keeps

Pages are copied whole, not redrawn. Our 20-page test scan of 12 MB gained 12 bytes. Each page image stayed byte for byte the same. In Chrome on a Mac, a 60-page grayscale scan of 45 MB was ready in 1.3 seconds, 0.2 percent smaller. A text PDF printed from Chrome shrank from 145 kB to 73 kB. Text and fonts stayed, but its accessibility tags, the structure screen readers follow, and its language setting were left out. Each PDF can be up to 300 MB and never leaves your browser.

Nothing leaves your computer

The PDF is read, reordered and written back inside your browser tab. No server sees it, no copy is stored on a server, and there is no queue to wait in, which makes this safe for contracts, payslips and scanned identity papers. To continue in another tool, PulsarKit may store a local copy of your input or result in this browser. It can remain after you close the tab or restart the browser. Clear PulsarKit’s site data to delete it.

Frequently asked questions

Why would I reverse the page order of a PDF?

Usually because a scanner produced the document backwards, with the last sheet first. It also helps when a colleague sends pages in descending order, or when a booklet was photographed from the back cover forwards.

How do I fix a scan that came out back to front?

Drop in the file and pick “Whole document” under “What to reverse”. Every page moves to the mirrored position, so page ten becomes page one. Check the first page of the result and the whole stack will be right.

What does the interleave mode do?

It merges a double-sided stack scanned in two passes. The first half is treated as fronts in order, the second as backs in reverse, and the result alternates them: 1, N, 2, N−1. Each back lands behind its own front.

Can I reverse only part of a document?

Yes. Choose the range mode and type something like 5-12. Only those pages are turned round; everything before and after keeps its place. Several ranges are allowed as long as they do not overlap.

Does reversing change the page orientation?

No. Each page carries its own rotation value and that value travels with the page. A landscape page stays landscape after the move. To change orientation you need the rotate tool instead.

How many files can I reverse at once?

Up to twenty files at a time, 500 MB in total. The mode you chose is applied to each file separately, and all the finished documents arrive together as one ZIP archive called pulsarkit-reversed.zip.

Is any quality lost when pages are reordered?

Not on the pages. They are copied whole, not redrawn, so images keep their exact compression and text stays as text. The PDF's accessibility tags, the structure screen readers follow, and its language setting are left out. On October 22, 2026, a 60-page scan of 45 MB came out 0.2 percent smaller. A 20-page text PDF printed from Chrome shrank from 145 kB to 73 kB, packed more tightly and without its tags.

What happens to bookmarks and links?

Page content, rotation, title and author are carried over. The outline is not, because its bookmarks pointed at page positions that no longer hold the same page and would send readers to the wrong place.