Rotate PDF pages

How to use it

1. Choose the PDF and pick the rotation: 90° clockwise, 180°, or 90° anticlockwise.
2. Watch the page previews turn, and tap any page to add it to the job or leave it alone — or name them by number, like "1-3, 7".
3. Download the corrected file.

Rotation is a single number, not a re-render

Every page dictionary in a PDF can carry a /Rotate entry holding 0, 90, 180 or 270. It tells any reader to turn that page clockwise by that many degrees before displaying it. Changing that number is the entire operation here: the content stream, the compressed image data of a scan, the font data and the page geometry all stay exactly as they were.

That is why the rotation is instant even on a 300-page scan, and why it cannot degrade anything. Doing the same job by opening each page as an image and turning it would decode and re-encode every JPEG, softening the text a little further each time anyone repeated it. Here there is no pixel to lose - a page rotated by 90 degrees four times comes back with content identical to where it started.

Why a rotated page can still print the wrong way round

/Rotate is a display instruction laid over the page’s real geometry. The MediaBox, the rectangle defining the page’s actual width and height, does not change. An A4 portrait page is still 595 by 842 points after a 90-degree rotation; only the viewer knows to present it as 842 by 595.

Well-behaved readers and printers honour that. Tools that read page dimensions directly and ignore /Rotate do not, and they are commoner than you would hope: some print drivers, imposition and booklet software, and library code that places PDF pages into another layout. If a page looks correct in every reader but emerges sideways from one specific downstream step, this is almost always the cause, and the durable fix is to export the document the right way up rather than to correct it afterwards.

Questions