Usually only one page is wrong: a landscape table in a portrait report, or a scan that went through the feeder sideways. You can fix that page alone. We turned page 2 of a three-page, 651 KB statement to the right and saved it; the result had page angles of 0°, 90° and 0°, weighed 648 KB, and was ready in about half a second. It downloads as the original name with “-rotated” added.
Which button turns which way?
Under each preview there are two arrow buttons: one gives the page a quarter turn counter-clockwise, the other a quarter turn clockwise. The preview turns as you click, so you can see the result before you save. An upside-down page needs two clicks, in either direction. Above the grid, “All pages left” and “All pages right” turn the whole document, which is the quick fix when an entire scan came out sideways.
Why can’t I press Save yet?
Until at least one page differs from how it started, there is nothing to save, and the tool says “Rotate at least one page first.” Four turns in the same direction bring a page back to where it began, and that counts as no change too.
What actually changes in the file?
Every PDF page carries a rotation value of 0, 90, 180 or 270 degrees, which viewers apply when they show the page. This tool adds your turns to that value and leaves the page content alone. That is why the sample above came out 3 KB smaller instead of bigger: nothing was drawn again, the file was only saved more compactly.
Can it straighten a slightly crooked scan?
No. Rotation here works in quarter turns only, so a page scanned a few degrees off stays a few degrees off. If you are also removing pages, Delete PDF pages handles that; if a rotated landscape page belongs in its own file, use Split PDF.