How to Combine Scanned Pages Into One PDF

Not everyone has access to a document scanner with an automatic feeder that outputs one clean multi-page PDF — a lot of scanning today happens one page at a time, either with a flatbed scanner or a phone camera, which leaves you with a folder of individual image files that need to become a single, correctly ordered document.

Check orientation before combining

Individually scanned or photographed pages are more likely to have inconsistent orientation than a fed scan, since each page was handled and positioned separately. Rotate any sideways pages to match the rest before combining them into a single PDF — fixing orientation after they're all one document means finding and correcting individual pages within the merged file instead.

Sort by page number, not by file name default

Phone photos usually get named by timestamp, not page order, so if you photographed pages out of sequence (page 3, then page 1, then page 2), the default file order won't match the document order. Rename or manually reorder before combining, since fixing page order after merging is more steps than getting it right first.

Trim scanner or photo background

A phone photo of a paper document usually includes some of the surface underneath the page — cropping each image down to just the page content, before combining, produces a cleaner final PDF than leaving visible desk or scanner-bed margins on every page.

Compress after combining, not before

Photos of paper documents are often larger files than necessary for the actual content — combine first, then run the finished multi-page PDF through compression once, rather than trying to individually optimize each source photo beforehand.