How to Rotate PDF Pages — Fix Sideways Scans and Upside-Down Pages

import { PDFDocument, degrees } from 'pdf-lib';
import fs from 'fs';
 
async function rotatePdfPages(inputPath, outputPath, rotationDeg, pageIndices = null) {
  // rotationDeg: 90, 180, or 270
  // pageIndices: null = rotate all pages, or array of 0-based indices
  
  const pdfBytes = fs.readFileSync(inputPath);
  const pdfDoc = await PDFDocument.load(pdfBytes);
  const pages = pdfDoc.getPages();
  
  const targetPages = pageIndices !== null
    ? pageIndices.map(i => pages[i]).filter(Boolean)
    : pages;
  
  targetPages.forEach(page => {
    const currentRotation = page.getRotation().angle;
    const newRotation = (currentRotation + rotationDeg) % 360;
    page.setRotation(degrees(newRotation));
  });
  
  const newBytes = await pdfDoc.save();
  fs.writeFileSync(outputPath, newBytes);
  console.log(`Rotated ${targetPages.length} pages by ${rotationDeg}°`);
}
 
// Rotate all pages 90° clockwise
await rotatePdfPages('input.pdf', 'output.pdf', 90);
 
// Rotate specific pages (0-based: pages 1, 3, 5 → indices 0, 2, 4)
await rotatePdfPages('input.pdf', 'output.pdf', 270, [0, 2, 4]);
 
// Rotate a single page 180°
await rotatePdfPages('input.pdf', 'output.pdf', 180, [0]);

from pypdf import PdfReader, PdfWriter
 
def rotate_pdf(input_path: str, output_path: str, angle: int, page_indices: list[int] | None = None):
    """
    angle: 90 (clockwise), 180, or 270
    page_indices: None = all pages, or list of 0-based indices
    """
    reader = PdfReader(input_path)
    writer = PdfWriter()
    
    for i, page in enumerate(reader.pages):
        if page_indices is None or i in page_indices:
            page.rotate(angle)
        writer.add_page(page)
    
    with open(output_path, 'wb') as f:
        writer.write(f)
    print(f"Saved {output_path}")
 
# Rotate all pages 90° clockwise
rotate_pdf('input.pdf', 'output.pdf', 90)
 
# Rotate pages 1 and 3 (0-indexed: 0 and 2) by 180°
rotate_pdf('input.pdf', 'output.pdf', 180, page_indices=[0, 2])
 
# Counterclockwise 90° = clockwise 270°
rotate_pdf('input.pdf', 'output.pdf', 270)

# Rotate all pages 90° clockwise
gs -dBATCH -dNOPAUSE -dSAFER \
   -sDEVICE=pdfwrite \
   -c "<</Orientation 1>> setpagedevice" \
   -f input.pdf \
   -sOutputFile=output.pdf
 
# Orientation values: 0=portrait, 1=landscape, 2=upside-down portrait, 3=upside-down landscape

# Rotate all pages 90° east (clockwise)
pdftk input.pdf rotate 1-endeast output rotated.pdf
 
# Rotate specific pages
pdftk input.pdf rotate 1east 3east output rotated.pdf
 
# Available directions: north, south, east, west, left, right, down
# east = 90° clockwise
# west = 90° counterclockwise
# south = 180°