About Rotate PDF
A sideways page in a PDF is a small thing that gets in the way every time. You open the file, tilt your head, swear gently, then either live with it or go hunting for a paid tool. It's a one-click problem, and it should stay a one-click problem.
Rotate PDF turns one or more pages by 90, 180, or 270 degrees and saves the corrected file. The rotation is written into the PDF itself, not just into the viewer's preferences, so the document reads correctly in every app, on every device, including print.
Rotating one page or a whole batch
Drop the PDF in and the page grid loads. Every page shows as a thumbnail with rotation buttons on it. Click the curved arrow to spin that page 90 degrees clockwise. Click again for 180. A third time for 270.
If everything needs the same treatment, use the Rotate All buttons in the toolbar. This is the common case for scans that came out the wrong way around, where the whole document needs to flip in one direction.
You can also rotate a specific selection. Hold shift and click a range of thumbnails, or use the page range field to type "2, 5-10". Then apply rotation only to that set. Handy when a scan picked up the form pages correctly but the exhibit pages sideways.
When sideways pages happen
Document scanners are the usual culprit. Auto-feeders pick up pages in mixed orientations, and the scanner doesn't always guess right. The first sign is a PDF where every other page is rotated.
Phone-scanned documents are next. You hold the phone in portrait, snap a landscape page, and the saved PDF rotates the page to fit the phone's natural orientation instead of the page's.
Sometimes a PDF arrives from a third party with a couple of pages flipped, usually a photo or a table that was inserted from a different source.
Things to keep in mind
Rotation here is content rotation, not just metadata. The pixels and text in the output PDF are oriented the way you set them. So if you print the file, the printer sends it through in the corrected orientation.
Resaving the file does not re-encode the pages. The internal page streams are preserved and just tagged with a new rotation. Quality stays identical to the input.
If a PDF is password-protected, unlock it first. Rotate respects encryption and will not bypass it.
Privacy
Like the other tools here, rotation runs entirely in your browser. Nothing uploads. Close the tab and the loaded PDF is forgotten.
Why view-only rotation isn't enough
Most PDF readers let you rotate a page on screen with a menu option, but that's a viewer setting. Close the file, open it on a different machine, and the page is back to its original orientation. Print the file and the printer sees the original orientation regardless of what the viewer showed you.
This matters when you're sending a document to someone else. The recipient opens it in their own reader, which has its own rotation preference, and they see the file the way it was saved, not the way you'd been looking at it. So a contract that looked correct on your screen because you rotated the viewer might land in their inbox with two pages sideways.
Rotate PDF writes the correct orientation into the file itself. The next person to open it, on any device, in any reader, sees the document the way it should be. Same with print. The fix is permanent and portable, not a viewer-side adjustment that only helps you.