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EPUB to MOBI Converter

Convert EPUB to MOBI online for free. Fast, secure, and high-quality conversion with no sign-up or software required.

  • Free to use
  • No file stored beyond 1 hour
  • Encrypted over TLS 1.2/1.3
  • No watermarks

Drag and drop your files here or click to upload.

Maximum file size is 1GB

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How it works

Three steps to your converted file

Everything happens in your browser tab - upload, pick a format, download. The heavy lifting runs on our servers.

  1. 01

    Upload your file

    Drag and drop, click to browse, or paste a URL. Batches take up to 20 files at once - 230+ input formats across video, audio, image, document, and archive types.

  2. 02

    Choose an output format

    Pick from over a hundred output formats. Filter by category or search by name - every option is open to everyone, no account needed.

  3. 03

    Convert & download

    Hit Convert and grab your download link moments later. Originals are erased when the job completes; results are cleared within about an hour.

EPUB to MOBI

Why convert EPUB to MOBI?

EPUB and MOBI are both ebook formats: EPUB is best for ebooks that reflow to fit any screen, MOBI for older Kindle ebooks.

  • Where MOBI works best

    Older Kindle ebooks.

EPUB vs MOBI: what's the difference?

PropertyEPUBMOBI
TypeEbookEbook
EditableNoNo
Opens inApple Books, Kobo, Google Play Books and most e-readersOlder Kindles and the Kindle app
Best forEbooks that reflow to fit any screenOlder Kindle ebooks

What is an EPUB file?

Electronic Publication

Developed By
IDPF / W3C
Initial Release
2007
MIME Type
application/epub+zip

EPUB (Electronic Publication) is an open e-book standard maintained by the World Wide Web Consortium (W3C), originally developed by the International Digital Publishing Forum (IDPF). It utilizes the Open Container Format (OCF) based on ZIP compression to package XHTML content, CSS styling, and XML metadata. EPUB supports reflowable content, allowing text to adapt to various screen sizes, and fixed-layout rendering for graphic-heavy publications. The current version, EPUB 3.2, supports HTML5, SVG, and JavaScript interactivity.

How to open an EPUB file

EPUB files require dedicated e-reader software as most operating systems do not natively render them. On desktop environments (Windows/macOS/Linux), Calibre is the industry-standard management tool, while Adobe Digital Editions handles DRM-protected files. For mobile devices, Apple Books (iOS) and Google Play Books (Android) provide native rendering. Browser-based extensions like EPUBReader for Chrome allow viewing without standalone software.

What is a MOBI file?

Mobipocket eBook Format

Developed By
Mobipocket SA
Initial Release
2000
MIME Type
application/x-mobipocket-ebook

The Mobipocket eBook format (MOBI) is a binary distribution format developed by Mobipocket SA in 2000, utilizing the Open eBook (OEB) standard and XHTML for reflowable content layout. Encapsulated within a Palm Database (PDB) container, MOBI files employ either the LZ77-based PalmDOC compression or the proprietary HUFF/CDIC algorithm to minimize file size. The format supports Digital Rights Management (DRM), metadata indexing, and javascript capabilities, serving as the foundational architecture for Amazon's proprietary AZW format before the adoption of KF8.

How to open a MOBI file

Native support for MOBI is restricted primarily to Amazon Kindle hardware and legacy Mobipocket readers. On Windows, macOS, and Linux, users require third-party eBook management software such as Calibre, which offers comprehensive viewing and conversion capabilities. Alternatively, the Kindle Previewer tool provided by Amazon or multi-format readers like FBReader and Sumatra PDF can render the unencrypted content of these archives.

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Why RunConvert

The fastest way to convert any file

Purpose-built for speed, privacy, and breadth of format support.

  • Convert EPUB to MOBI in seconds

    Every EPUB to MOBI conversion runs on our servers, so your device stays fast and the output quality stays intact.

  • Fast, cloud-powered

    No queue, no waiting. Files are processed on high-performance servers and returned in seconds, even for large files.

  • Secure & private

    Encrypted in transit and never shared with anyone. Uploads are erased the moment your job completes, and results shortly after.

  • Free - no account needed

    Convert without creating an account - no credit card, no trial clock. Sign in only if you want history and higher daily limits.

Developer API

Convert EPUB to MOBI via API

Automate EPUB to MOBI conversions in three steps: create a job, upload your file, then poll for the result.

Replace YOUR_API_KEY with your RunConvert API key. Get your free API key at runconvert.com/api.

# 1. Create job
curl -X POST https://api.runconvert.com/v3/jobs \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "tag": "epub-to-mobi",
    "tasks": {
      "upload-file": {
        "operation": "import/direct/upload"
      },
      "convert": {
        "operation": "convert",
        "input": "upload-file",
        "input_format": "epub",
        "output_format": "mobi"
      },
      "export-result": {
        "operation": "export/url",
        "input": "convert"
      }
    }
  }'

# 2. Upload your file (upload_url of the upload-file task in the response)
curl -X PUT "$UPLOAD_URL&filename=input.epub" --upload-file input.epub

# 3. Poll for result
curl https://api.runconvert.com/v3/jobs/$JOB_ID?include=tasks \
  -H "Authorization: Bearer YOUR_API_KEY"

FAQ

Frequently asked questions

Common questions about converting EPUB to MOBI with RunConvert.

Upload your .epub file, select MOBI as the output format, and click Convert. Note that newer Kindle devices prefer AZW3 or EPUB sent via Send-to-Kindle.

Newer Kindles support EPUB directly through Amazon's Send-to-Kindle service, so MOBI is mainly needed for older Kindle hardware or specific third-party apps.

Ready to convert EPUB to MOBI?

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