Split PDF Page in Half cuts every page of a PDF vertically into two separate pages, so a document with two pages printed side by side on each sheet becomes a normal document with one page per sheet. It is the fix for book and magazine scans, for presentations printed two slides per page, for booklets exported as spreads, and for any file where two logical pages share one physical page. The cut does not have to be exactly in the middle. The preview shows the page with a red line that you drag to where the content actually divides, and the slider fine-tunes the position for cases where one half is wider, such as a scan with a margin on one side. Pages that should not be cut, like an upright cover, are recognised by their portrait shape and left whole. The halves are produced without re-rendering, so text stays text, images keep their resolution and the file size barely changes. All processing happens in the browser, nothing is uploaded. To split the result into several files by page range afterwards, use PDF Splitter, and to trim the edges of the new pages use PDF Crop & Resize.
Scanning a book two pages at a time is the fastest way to digitise it, which is why so many archive scans, library copies and phone-camera captures end up as spreads. The cost appears later. A spread is too wide to read comfortably on a phone or e-reader, so every page has to be zoomed and panned. PDF page numbers drift away from the printed page numbers, which makes citing and bookmarking confusing. OCR and text-to-speech tools often read a line straight across both pages instead of finishing the left page first. Printing a spread shrinks two pages onto one sheet. Cutting each spread at the spine solves all of these at once. A few practical notes help get a clean result. Place the line in the gutter, the shadow or white strip where the pages meet, rather than on the text; a small amount of the opposite page at the edge is harmless and can be trimmed later. If the book was scanned in two sessions, the spine is often in a different place in each half of the file, and moving the line for individual pages handles that without starting over. Scans saved upright with the spread turned sideways should be rotated first with PDF Rotate, so the spine runs from top to bottom before you split. After splitting, PDF Crop & Resize removes dark scanner edges, Make All PDF Pages Same Size evens out pages that came out at slightly different widths, and PDF Page Count Checker confirms the final page count matches the book.