How to Reorder Pages in a PDF

A stack of paper fed face-up into a scanner comes back reversed. An appendix that was written last needs to sit before the annexes. Reordering fixes both, and it is one of the few PDF operations where being methodical genuinely pays off.

The reverse case

Reversal is by far the most common reordering job, and it needs no configuration at all. Leave the order field empty and the whole document is flipped end to end. If your scan is simply backwards, that is the entire fix.

Defining a custom order

For anything else, you write the sequence explicitly. The list is read left to right and becomes the new page order, so '3, 1, 2' puts the third page first. Ranges are allowed, which keeps long sequences short: '5-20, 1-4' moves the first four pages to the end of a twenty-page document.

1. Upload the PDF and note the total page count.
2. Write the full sequence you want, using ranges wherever pages stay consecutive.
3. Run the tool.
4. Compare the output page count against the original — if it is lower, you left pages out.

Any page you do not list is dropped from the result. That is occasionally useful and frequently accidental, so the page count check is the important step.

A trick for interleaved scans

Scanning a double-sided document on a single-sided scanner produces all the fronts, then all the backs. For a ten-page document that means positions 1 to 10 are the odd pages and 11 to 20 are the even ones, often reversed. Merge the two passes, then reorder with an explicit sequence: 1, 20, 2, 19, 3, 18 and so on. Tedious once, and then you have the pattern for next time.

Conclusion

Reversal needs nothing. Custom orders need the whole sequence, ranges to keep it manageable, and a page count check at the end. Beyond that, reordering is one of the safest edits you can make, because the original file is untouched.