How to fix sideways PDF scan pages

You open a finished scan of a contract and half the pages are lying on their side. To read clause 7 you have to tilt your head or turn the laptop. It stings more when the document runs long and a sheet-fed scanner pulled some sheets in landscape, some upside down, and a couple of spreads came through mirrored. You cannot send a PDF like that to a counterparty or to accounting. It looks sloppy, and some people simply will not be able to read it.

Usually the file itself is fine. The scanner and its driver are the culprits. The automatic feeder flips a sheet, the duplex mode mixes up odd and even pages, and the auto-rotate feature guesses orientation from the text and gets it wrong on forms, tables, and pages with stamps. Add to that scans from phone apps where the phone was held horizontally, and old archives stitched together from mixed sources. One thing matters here: every PDF page has its own rotation attribute. That means you can fix orientation page by page without rescanning the stack and without losing quality. Rotation does not recompress the image and works with any kind of scan, black and white or color.

How to rotate pages, step by step

1. Open rotate-pdf and upload your scan. You can drag the file straight into the browser window. 2. Wait for the thumbnails of every page to appear. That way you can see at a glance which ones are sideways or flipped. 3. Find the problem pages and turn each one 90 degrees clockwise or counterclockwise with the button. For upside-down pages, click twice (180 degrees). 4. Check against the thumbnail: the top edge of the text should point up, and headers and page numbers should sit where they belong. 5. If you need to turn the whole document one way at once, apply the rotation to all pages in a single action, then fix the exceptions one by one. 6. Download the corrected file and open it in a normal viewer to confirm the orientation stuck.

What can go wrong

• The page is straight on screen but sideways in print. The viewer respects the Rotate flag and the printer ignores it. After a turn in rotate-pdf the orientation is locked hard and matches on screen and on paper.
• You rotated the wrong page. In a long batch it is easy to lose your place. Go by what the thumbnail shows, not by the page number, and confirm you are fixing the page that was actually flipped.
• Odd and even pages swapped in a duplex scan. Then every second page comes out upside down. Turn those selectively by 180 instead of rotating the whole document.
• Extra or blank pages from the feeder. If the scanner grabbed blank backs, remove them in remove-pages. A rotation will not turn a blank page into a useful one.
• A slight skew rather than a rotation. A tilt of 2 or 3 degrees is a feed defect, not a 90-degree turn. Fix a page like that by rescanning or by trimming the margins in crop-pdf.
• A huge file built from dozens of scans. When there are too many pages, it is easier to split the stack into parts with split-every-n-pages, fix the orientation in each, and put it back together.

What to check before you send

• Every page reads without tilting your head, and the text runs top to bottom.
• Page numbers and headers sit at the bottom or top, not off to the side.
• The spreads that were flipped now match the orientation of their neighbors.
• The file opens correctly in the browser, in Acrobat, and in print preview.
• No blank or duplicate pages are left after your edits.

What comes next

If the scan arrived in several parts to begin with, combine them into one document with merge-pdf after you have fixed the orientation of each part. When you need to pull only the correct spreads out of a large stack, split-pdf and extract-pages help, and the easiest way to sort out the page order is organize-pdf. Every tool runs in the browser with no sign-up, and the corrected file is ready to send the moment you download it.