Kindlegen guide: amazon's official ebook converter (still useful in 2026)

KindleGen is Amazon’s official command-line ebook converter. Though discontinued, it remains essential for professional ebook creation.

What is KindleGen?

KindleGen converts HTML, XHTML, and OPF files into Kindle-compatible MOBI/AZW3 format. It was Amazon’s recommended tool for years and still produces the most standards-compliant output.

Important: Amazon stopped providing KindleGen downloads in 2023. The last version is 2.9. You can still find it archived online or extract it from Kindle Previewer.

Why Still Use KindleGen?

Reason	Explanation
Standards compliance	Produces Amazon’s most compatible MOBI files
Precise control	You control every aspect of the output
Batch processing	Can script conversions for many books
No GUI needed	Perfect for automation and CI/CD
Lightweight	10MB vs 400MB+ for Kindle Previewer

How to Get KindleGen

Since Amazon removed official downloads:

1. Install Kindle Previewer (the newest version)
2. Navigate to the installation folder:
   • Windows: C:\Program Files\Kindle Previewer 3\lib\kindlegen\
   • macOS: /Applications/Kindle Previewer 3.app/Contents/MacOS/lib/kindlegen/
3. You’ll find the kindlegen executable there

Basic Usage

Command Line

kindlegen mybook.opf

This generates mybook.mobi in the same folder.

Common Options

kindlegen mybook.opf -o output.mobi    # Specify output filename
kindlegen mybook.opf -verbose          # Detailed output
kindlegen mybook.opf -c1               # Compression level (0-2)
kindlegen mybook.opf -gif              # Convert GIFs to PNGs
kindlegen mybook.opf -locale en        # Set language

Complete Workflow

Step 1: Prepare Your Files

Create an OPF package file and your HTML content:

mybook/
├── content.opf        # Metadata and manifest
├── toc.ncx            # Table of contents
├── chapter-01.html    # Chapter 1
├── chapter-02.html    # Chapter 2
├── styles.css         # CSS styles
└── images/
    ├── cover.jpg
    └── image1.jpg

Step 2: Create OPF File

<?xml version="1.0" encoding="utf-8"?>
<package xmlns="http://www.idpf.org/2007/opf" version="2.0" unique-identifier="BookId">
  <metadata>
    <dc:title>My Book Title</dc:title>
    <dc:creator>Author Name</dc:creator>
    <dc:language>en</dc:language>
    <dc:identifier id="BookId">978-0-000-00000-0</dc:identifier>
  </metadata>
  <manifest>
    <item id="cover" href="images/cover.jpg" media-type="image/jpeg"/>
    <item id="chapter1" href="chapter-01.html" media-type="application/xhtml+xml"/>
    <item id="chapter2" href="chapter-02.html" media-type="application/xhtml+xml"/>
    <item id="css" href="styles.css" media-type="text/css"/>
    <item id="ncx" href="toc.ncx" media-type="application/x-dtbncx+xml"/>
  </manifest>
  <spine toc="ncx">
    <itemref id="cover" linear="no"/>
    <itemref id="chapter1"/>
    <itemref id="chapter2"/>
  </spine>
</package>

Step 3: Run KindleGen

kindlegen content.opf -verbose -c1

Step 4: Test the Output

1. Open the generated .mobi file in Kindle Previewer
2. Check formatting on multiple device simulations
3. Verify table of contents links

KindleGen vs Modern Tools

Feature	KindleGen	Kindle Previewer	Calibre
Format support	HTML → MOBI/AZW	EPUB → KFX	20+ formats
Quality	★★★★★	★★★★	★★★★
Ease of use	★★ (command line)	★★★★ (GUI)	★★★★★ (GUI)
Automation	✅ Excellent	❌ No	⚠️ Limited
Output format	MOBI, AZW3	KFX	MOBI, AZW3, EPUB

Pro Tips

• Use -c1 compression — best balance of size and quality
• Validate with EpubCheck before running KindleGen
• For KFX output, use Kindle Previewer instead (KindleGen doesn’t support KFX)
• Batch convert with a shell script:

  for f in *.opf; do
    kindlegen "$f" -c1
  done

• The 64-bit version (extracted from Kindle Previewer) works better on modern systems

Limitations

• Discontinued — no new features or bug fixes
• Only outputs MOBI/AZW3 (not KFX)
• Doesn’t support EPUB3 features
• Command-line only (no GUI)
• Doesn’t validate EPUB input