ページ順を逆にする

このツールでできること

This turns the document back to front: the last page becomes the first and so on. Pages are copied rather than re-rendered, so it costs nothing in quality.

Almost always to fix a scanner. Document feeders that stack their output face-up produce a PDF that reads from the last page backwards, and the fix is a single pass through this tool. It is also useful for documents in right-to-left binding order that were assembled left to right.

仕組み

1. Drop the PDF onto this page.
2. Leave the page range empty to reverse the whole document.
3. To flip only part of it, give a range - those pages are reversed among themselves and everything else stays where it is.
4. Press Reverse.
5. The download starts on its own.

Reversing a range does something more careful than it might sound. The selected pages swap positions among themselves, and every page outside the selection stays exactly where it was. Reversing pages 3 to 6 of a ten-page document leaves pages 1, 2, 7, 8, 9 and 10 untouched. A naive implementation that lifted the range out and put it back would shuffle the surrounding pages, which is a subtle way to lose a document's structure.

If your scan is both reversed and double-sided, this tool is only half the fix. Scanning a double-sided stack on a single-sided feeder produces two files - fronts in order, backs reversed - and what you need is Alternate and mix, which interleaves them and reverses the second automatically.

Bookmarks are re-pointed at the pages' new positions, so a table of contents keeps working after the flip.

Everything happens in your browser, so a 500-page scan is reversed without a byte being uploaded.