How to rotate a PDF and save it the right way up

The usual version of this problem goes like this. A scanned page opens sideways, you turn it in your PDF reader, it looks right, and the next time anyone opens the file it is sideways again. The reader turned your view of the page. Nothing was written to the file.

Rotation is a number stored on each page

PDF page rotation is a value in degrees, kept in the page’s /Rotate entry, that tells a reader how to display the page. The drawing instructions and images on the page are not touched; the reader applies the turn when it puts the page on screen. Rotating is therefore a property change rather than a transformation of content, which means nothing is re-rendered and no quality is lost.

Two practical consequences follow. A rotation that you only see in one app is not in the file. And because each page holds its own value, a scan can have pages at every angle in the same document, and fixing it means changing the value on the right pages and no others.

Rotating pages, step by step

1. Open Rotate PDF and choose Add a PDF, or drop the file in. If it is protected, enter the password when asked.
2. Thumbnails of every page appear. Click the pages that are the wrong way up; each one you select is outlined. The note in the panel counts them (“3 selected pages will turn”). If you select none, it reads “No pages selected, so every page will turn”.
3. Under Turn by, choose 90°, 180° or -90°. The thumbnails turn in place to show how the pages will come out, so you can confirm the direction before saving.
4. Press Rotate PDF, then download the file, which is named after the original with “-rotated” added.

One run applies one direction. If some pages need 90° and others -90°, turn the first set, download, add the downloaded file and turn the second set. Do another clears the loaded file, so adding the new one is the step that carries your first fix forward.

There is no automatic orientation detection. It would guess wrong on tables and diagrams often enough to be worse than choosing, so the choice is yours.

Why stored rotation goes wrong

Turning a page that already has a rotation has to add to the existing value. Two shortcuts get it wrong. A tool that replaces the value writes your chosen angle over whatever was there, so a page stored at 90° and turned by 90° stays at 90° and the tool appears to have done nothing. A tool that adds without wrapping leaves values such as 450° or 540° in the file, which some readers normalise and others display sideways. That second case is the usual cause of a file that is upright in one app and sideways in another.

The tool adds the turn to the stored value and keeps the remainder after dividing by 360. In its code, the -90° option is a turn of 270°, which arrives at the same orientation.

Stored value	You choose	A tool that replaces	A tool that adds without wrapping	Add, then wrap (this tool)
0°	90°	90°	90°	90°
90°	90°	90°, no visible change	180°	180°
270°	-90° (270°)	270°, no visible change	540°	180°
270°	90°	90°	360°	0°
180°	-90° (270°)	270°	450°	90°

A file that already carries an out-of-range value is settled the same way. A page stored at 540° and turned by 90° comes to 630°, and the remainder after 360 is 270°, so the saved value is one every reader reads alike.

Rotating your view is not rotating the file

Many PDF readers have a rotate command intended for reading: it turns the page on your screen so you can read a landscape table, and it is not saved into the document. That is useful, and it is the reason a fix can seem to vanish. The test is simple. Close the file, open it again, ideally in a different app, and look. If it is sideways, the rotation was never written.

File size is a second clue. A real rotation changes very little, because only a small number per page has changed. Saving does repack the file’s internal objects, the structural step whose effect is measured in what lossless PDF compression saves, measured, so a small difference in size either way comes from the repack rather than the rotation.

Other ways to rotate PDF pages

On macOS, Preview writes rotation into the file. Select the pages in the sidebar (View → Thumbnails), choose Tools → Rotate Left or Rotate Right, and save; the saved file keeps the turn.

On the command line, qpdf rotates a page range and writes a new file:

qpdf input.pdf rotated.pdf --rotate=+90:1-3

That turns pages 1 to 3 by 90° and leaves the rest as they were.

On Windows, there is no built-in method for rotating PDF pages. The Photos app rotates images, not pages inside a PDF.

	Rotate PDF	macOS Preview	qpdf
Choosing pages	Click thumbnails, or none for every page	Select thumbnails in the sidebar	A page range after the colon
Directions	90°, 180°, -90°	Left or right	The angle you type
Written into the file	Yes, in the download	Yes, when you save	Yes, in the new file
Preview before saving	Thumbnails turn in place	The page turns on screen	None
Your file is sent anywhere	No	No	No
Runs on	Any modern browser	macOS	Any system, once installed

Watching the rotation happen locally

Rotation is about the cheapest edit there is, which makes it a quick way to check that the tool keeps your file local. With the developer tools open on the Network tab, add a document, turn a page and download. The list shows the site’s own code arriving, including the PDF library when the first file goes in, and nothing leaving with your document in it. The rotated file is written by your browser.

Rotate PDF is free to use. A document that also needs its margins trimmed can go through Crop PDF next, and pages in the wrong order can be fixed with Organise PDF.