Alternate and Mix PDF
Interleave pages from two PDFs, taking one from each in turn. Fixes single-sided scans where fronts and backs ended up in separate files.
Upload PDF Files
About This Tool
This exists to solve one specific and very common problem. You have a stack of double-sided paper and a scanner that only does one side. You scan all the fronts, flip the stack, scan all the backs - and end up with two files that need to be interleaved 1, 1, 2, 2, 3, 3 rather than concatenated.
Alternate merge takes one page from each document in turn. Load the fronts and the backs and you get a correctly ordered double-sided document without dragging 80 thumbnails into position by hand.
The reverse option handles the flipped stack: when you turn the pile over, the backs come out in the opposite order, so reversing the second document during the merge is usually exactly what you need.
How to Use
Load both documents
Add the fronts first, then the backs. Up to 10 files can be interleaved.
Reverse if needed
If the second stack was scanned after flipping the pile, enable reverse so the backs line up with their fronts.
Check the preview
The interleaved order is listed page by page. Confirm page 2 is the back of page 1.
Merge and download
Save the correctly ordered document.
Use Cases
Single-sided scanner, double-sided paper
Fronts and backs in two files, interleaved into one correct document.
Translations side by side
Alternate original and translated pages so each is followed by its counterpart.
Forms and their attachments
Interleave each form page with its supporting document.
Frequently Asked Questions
What if the two files have different page counts?
Interleaving continues until one runs out, then the remaining pages are appended in order.
When do I need the reverse option?
When you flipped the whole stack before the second scan, which puts the backs in opposite order. This is the usual case.
Can I interleave more than two documents?
Yes, up to 10. Pages are taken from each in rotation.
How is this different from normal merge?
A normal merge appends one document after another. This weaves them together page by page.