Interleave PDF
Merge two PDFs page by page, alternating A-B-A-B.
Built for duplex scanners: feed the front-side scan first, the back-side scan second, and the pages come out in reading order. At least two files are required.
How to use Interleave PDF
Add your file
Click the drop area or drag your file onto it. Everything is read locally — the file is never transmitted.
Set the options
Use the controls below. Where a preview is available, check it before you continue.
Download the result
Press the action button. The output is generated in your browser and saved to your normal downloads folder.
Your file never leaves this device. No upload, no account, no watermark.
Related tools
Common questions
Is my file uploaded to a server?
No. This tool runs entirely in your browser. There is no upload endpoint, and you can verify it yourself in your browser's network tab — no request carries your document.
Is there a file size limit?
No artificial limit. The real constraint is your device's available memory, since the whole document is held in the tab while it is processed.
Does it work offline?
Once the page has loaded, yes. All libraries are served from this site rather than a third-party CDN, so the tools keep working without a connection.
Will the output have a watermark?
Never. Nothing is stamped on your document, and there is no paid tier that removes one.