How to Reduce the Number of Pages in a PDF
"Trim this PDF down" usually means one of two slightly different jobs, and picking the wrong one just makes more work. Sometimes you know exactly which pages you don't want (a blank cover sheet, a duplicate page a scanner produced by accident). Other times it's easier to describe what you do want to keep, especially out of a long document where the useful part is a small fraction of the whole.
If you know what to remove
Use the PDF Page Remover. Upload the file, select the specific pages to delete, and download what's left.
If it's easier to say what to keep
Use the PDF Page Extractor instead. Select the pages you want, and it builds a fresh PDF from just those, in the order you pick them — genuinely useful for pulling three relevant pages out of an 80-page report without touching the rest.
A quirk worth knowing about duplicate pages
Office scanners occasionally produce an accidental duplicate page when a document jams or gets fed through twice. If you suspect that's what happened rather than deliberately checking every page yourself, the PDF Duplicate Page Finder can flag repeated pages automatically instead of you paging through the whole document manually.
After trimming, check the file size too
Removing pages reduces page count, obviously, but if the original problem was really file size rather than page count, run the trimmed result through the PDF Compressor as well — a 40-page PDF full of high-resolution scans can still be huge even after you've cut it down to 10 pages.