Crop PDF reads each page's existing rotation and remaps the top, right, bottom, and left margins to match the page's visually displayed edges before cropping.
Apple's documentation for Preview describes cropping a page to hide content and rotating it to change orientation as two related but separate actions. Crop or rotate a PDF in Preview on Mac - Apple Support
Crop PDFCrop Rotated PDF Pages
Upload the PDF file containing rotated pages.
Set each margin field to match how much of the rotated edge to trim.
Click the crop button to process the document.
Checking Cropped Edges on Rotated Pages
Download the finished PDF from the results screen.
Open the downloaded file and inspect the trimmed edges on the rotated pages.
Compare the visible content on every rotated page carefully against the intended crop boundaries you originally specified.
Continue with Crop PDF margins in points or Crop PDF does not erase content.
Frequently Asked Questions about Crop Rotated PDF Pages
How do I upload a rotated PDF for cropping?
Upload the PDF file using the link below.
Where do I set the crop margins?
Select the margin inputs to define the crop area.
How do I redo the crop on a different rotated file?
Refresh the page and select a new rotated PDF to crop.
How do I tell which edge became the top after rotation?
Rotate the physical printout or your screen to match the page's original orientation.