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TXT to MOBI Converter

Convert TXT 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.

TXT to MOBI

Why convert TXT to MOBI?

TXT can be edited, while MOBI looks the same on every device.

  • Where MOBI works best

    Older Kindle ebooks.

TXT vs MOBI: what's the difference?

PropertyTXTMOBI
TypeDocumentEbook
EditableYesNo
Opens inEvery computer and phoneOlder Kindles and the Kindle app
Best forPlain text without any formattingOlder Kindle ebooks

What is a TXT file?

Plain Text File

Standardized By
American Standards Association (ASCII)
Initial Release
1963 (ASCII)
MIME Type
text/plain

A TXT file is a standard plain text document that contains unformatted text, free of styling information such as fonts, bolding, or layout parameters. It stores data as a sequence of characters encoded in standards such as ASCII, UTF-8, or UTF-16, making it universally readable across all computing platforms. The format relies solely on control characters for line breaks (CR/LF) and spacing, serving as the fundamental data type for code source files, logs, and simple documentation.

How to open a TXT file

TXT files possess universal native support on all operating systems. Windows opens them by default with Notepad, macOS uses TextEdit, and Linux distributions utilize editors like Gedit or Nano. Because they contain no proprietary formatting, they are also viewable in any web browser and can be imported into virtually any word processing or data management software without conversion.

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.

More tools

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Why RunConvert

The fastest way to convert any file

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

  • Convert TXT to MOBI in seconds

    Every TXT 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 TXT to MOBI via API

Automate TXT 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": "txt-to-mobi",
    "tasks": {
      "upload-file": {
        "operation": "import/direct/upload"
      },
      "convert": {
        "operation": "convert",
        "input": "upload-file",
        "input_format": "txt",
        "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.txt" --upload-file input.txt

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

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