How rotation stacks
Each page carries its own rotation setting, and whatever you choose here is added to what's already there — not replaced. A page already turned 90° that gets another 90° ends up at 180°, not back at 90°. If a page looks wrong after rotating, running it through again with the same or a different angle fixes it.
Common questions
Can I rotate just some pages?
Yes. Choose "Specific pages" and enter the pages or ranges to rotate, such as 2, 5-7. Everything else is left exactly as it was.
What if a page is already rotated?
The rotation you choose is added to whatever rotation the page already has, so a page already turned 90 degrees plus a further 90 degree rotation ends up at 180.
Does rotating affect the page content or quality?
No. Only the page's rotation flag changes, which every PDF viewer respects when displaying it. The underlying content is untouched.