My back pages were scanned in reverse order. Can the tool flip them?

Not automatically — the mix always runs front-to-back through both files. Reverse the backs PDF first: the Reorder PDF Pages tool lets you drag pages into reverse order (manageable for a typical scan), then mix. Better yet, when scanning backs, flip the stack so they come out in forward order.

What if the two files have different page counts?

The tool alternates for as long as both files have pages, then appends whatever remains from the longer file. For a duplex scan, mismatched counts usually signal a misfeed — count your sheets before trusting the result.

Which file should I upload first?

The one whose page should come first in the output — for double-sided scans, the fronts. The first file added always contributes page one.

Can I mix three or more files?

The tool interleaves exactly two. For a three-way weave, mix two files first, then mix the result with the third — though the alternation pattern gets more complex, and a manual pass in the Merge tool's drag grid may be easier to verify.

Alternate & Mix PDF

Interleave pages from two PDF files. Files are processed entirely in your browser.

Drop PDF files here or browse

Max 100MB per file · Up to 2 files

About Alternate & Mix PDFs

When you scan a double-sided document on a single-sided scanner, you end up with two PDFs: one with all the fronts, one with all the backs. What you actually want is one file in reading order — front 1, back 1, front 2, back 2. Convertora's alternate-mix tool interleaves the two files exactly that way, taking one page from each in turn until both are exhausted.

The mixing rule is simple and strict: the first file you add leads. Page 1 of file A, then page 1 of file B, then page 2 of A, page 2 of B, and so on. If one file is longer, its leftover pages are appended at the end rather than dropped, so nothing silently disappears.

Like the rest of Convertora, the interleave happens in your browser — both PDFs are read in memory, pages are copied alternately into a new document, and the result is handed straight back to you.

How to use it

1Scan the front sides of your stack, then the back sides, producing two PDFs.
2Upload both files (up to 100 MB each). The file you add first becomes 'A' and contributes the first page.
3Click Mix. Pages are interleaved A1, B1, A2, B2… with any surplus pages from the longer file appended at the end.
4Download the combined file, delivered as mixed.pdf.

Common use cases

Reassembling double-sided documents scanned in two passes on a single-sided scanner or phone app.
Interleaving a translated document with its original, page by page, for side-by-side review.
Merging two halves of a document captured by two people scanning alternate sheets.
Weaving answer pages into an exam paper so each question is followed by its solution.

Frequently asked questions

Tips

Check the first four pages of the output before archiving — a reversed back-stack reveals itself immediately as front 1 followed by the last page's back.
If your scanner duplicates or skips a sheet, the alternation goes off-by-one from that point. Fix the individual file with Delete Pages or Reorder before mixing rather than after.

100% private — runs in your browser

Convertora processes everything on your device using JavaScript and WebAssembly. Files never leave your browser, are never uploaded to a server, and are never seen by us or anyone else. The moment you close the tab, the data is gone — there is no temporary cloud copy, no log entry, no retained backup.

Because the work happens locally, processing speed depends on your device — but there are no rate limits, no daily caps, and no file size restrictions beyond what your browser can handle in memory. No signup, no account, no payment. The tool works the same in incognito mode, on a corporate network, or after the page has loaded once, even with the network disconnected.