Interleave PDFs
Alternate pages from two PDFs, including reversed scans.
Private: it runs in your browser and your file is never uploaded. How to check it
The list above shows the first and second file.
Reverse order helps when the backs were scanned from the last sheet first.
Your files are processed here, on your device
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How we handle your data →How to use this tool
- Add fronts and backs as two separate PDF files.
- Choose which starts and reverse the second if its sheets run backward.
- Check the first pairs and any remaining sheets at the end.
An example you can verify
Restore the order of a double-sided scan saved as two separate files.
Example input
sample-3-pages.pdf (A1, A2, A3) + sample-2-pages.pdf (B1, B2).
Expected result
A1, B1, A2, B2, A3.
Try these files containing fictitious data:
Download sample · sample-3-pages.pdfDownload sample · sample-2-pages.pdfReverse the second file if backs were scanned from the last sheet. Remaining pages are appended at the end; check whether any backs are missing.
Interleave PDFs: uses and practical guidance
Interleaving two PDFs addresses a common limitation of scanners that capture only one side at a time. You scan the fronts into one file and the backs into another. The tool alternates one page from the first file with one page from the second. It does not read the written content or automatically determine which back belongs to which front. Correct preparation of both input sequences is essential to reconstructing the document.
Inspect the first and last pages of both files before processing. Some scanning workflows save backs from the last sheet towards the first; reverse the second file when this is necessary to align the pairs. Three fronts and two backs produce five pages in this order: A1, B1, A2, B2, A3. Unmatched pages are appended at the end. The tool does not invent blank pages to complete missing pairs or diagnose gaps in the original scan.
Check the first two pairs and the end of the downloaded PDF. One omitted back can shift every later pair even when the total page count looks plausible. Insert a blank page in the appropriate input position when an empty side needs to be retained. Merge PDF serves a different workflow, combining complete documents one after another. Keep both original scans so that you can correct the sequence without scanning all of the physical sheets again.
A practical check before using the result
A useful trial uses pages labelled A1, A2 and A3 for fronts and B1, B2 and B3 for backs. If matching pairs do not alternate in the output, correct the input sequence before using actual scans. For unequal files, record which sheet should remain unmatched. This distinguishes an expected extra page from an omitted back. Inspect visible images and numbers when a scanner inserts its own separator sheet at the start, since that separator also participates as a page and can shift every later pairing in the resulting document.
Settings and limits
Add exactly two PDFs. Choose which starts and the second file’s page order.
Exactly 2 PDFs, up to 120 MB per batch and 500 output pages. Encrypted PDFs are unsupported. Check links, forms, annotations and signatures after editing a document. Available memory may require smaller batches.
Frequently asked questions
What if one file has more pages?
Remaining sheets are appended once the other file ends. Blank sheets are not inserted to complete pairs.
Are my files uploaded?
No. Your file and result are processed locally in your browser. No account is needed.
Is it free, and do I need to sign up?
Yes, it is free. You do not need to sign up, create an account or install an app, and there is no daily quota: open the tool and use it. The only limits are file sizes, which protect your device’s memory.
Does it leave a watermark on the result?
No. Snipshed adds no watermark, logo or text of its own to the files you download: the result is yours exactly as you configured it.
Is quality lost?
No. Pages are copied as they are into the new PDF, without recompressing text, images or graphics, so quality is identical to the original.
Does it work on iPhone and Android?
Yes, from your phone’s browser (Safari, Chrome…) and without installing any app. When it finishes, the file is saved from the browser itself: on iPhone it appears in the Files app and on Android in Downloads. With very large files the phone may run out of memory; try a smaller file or a computer.
Guides
Combine documents, supporting evidence and appendices into an ordered copy, then check it before sharing.
Rebuild double-sided scans by alternating files and correct back-side pages saved in reverse order.
Create alternating groups, count from the first sheet and run a test before manual double-sided printing.