Any file up to 500 MB. Drop several files and they come back as one ZIP. Many image, audio and video conversions run in your browser; anything else is uploaded and removed within the hour.
Convert your HTML web documents into the MOBI format specifically optimized for Kindle e-readers. This tool is perfect for web developers and writers who want to transform web-based content into portable, offline-readable e-books.
HTML is a markup language designed for web browsers, relying on external stylesheets and scripts to define its structure. In contrast, MOBI is a proprietary document format created for e-ink devices, which packs text and essential formatting into a single, static file. Our converter bridges this gap by parsing the HTML tags and mapping them to the MOBI structure, ensuring that your web content is properly encapsulated for e-reader compatibility.
The conversion process is strictly lossless, preserving all your original text and layout hierarchy. The resulting MOBI file maintains the exact content fidelity of your source HTML document.
We built this project so anyone can convert files without paywalls, accounts, or hidden limits. Here is what that promise means in practice.
Every converter on ConvertX is free to use: no trials, no premium tiers, and no credit packs. We will never put core conversion features behind a subscription. Whether you convert one photo or a hundred files a week, the price stays zero.
Many image, audio, and video conversions run entirely in your browser. Your files never leave your device for those jobs. When server processing is required for documents or specialized formats, uploads are handled securely and removed automatically — typically within one hour.
A quick guide to strengths and trade-offs of popular formats — so you pick the right one before converting.
Office files, PDFs, ebooks, and plain text.
Common extensions: PDF, DOCX, XLSX, PPTX, ODT, EPUB, TXT
Raster and vector graphics for web, print, and photography.
Common extensions: PNG, JPG, WebP, AVIF, GIF, SVG, HEIC, TIFF
Clips, streams, screen recordings, and movies.
Common extensions: MP4, WebM, MOV, MKV, AVI, MPEG
Music, podcasts, voice recordings, and sound effects.
Common extensions: MP3, WAV, FLAC, OGG, AAC, M4A, OPUS
