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OTB to FB2 Converter

Transform OTB graphics into FB2 e-book files easily

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No Install Required

The entire OTB to FB2 conversion happens in your browser. No plugins, no desktop apps — just upload, convert, and download.

E-Reader Ready

Convert OTB images into FB2 format, ready for e-readers and reading apps. FictionBook 2.0 is supported by major e-book platforms.

Secure Processing

Uploaded OTB images are erased right after conversion, and the resulting FB2 files are purged within 24 hours — your data stays private.

How to convert OTB to FB2

1

Select files from Computer, Google Drive, Dropbox, URL or by dragging it on the page.

2

Choose fb2 or any other format you need as a result (more than 200 formats supported)

3

Let the file convert and you can download your fb2 file right afterwards

About formats

OTB (Over-the-Air Bitmap) is a monochrome image format developed by Nokia as part of their Smart Messaging specification in 1997, designed for transmitting small graphics — operator logos, group graphics, and picture messages — to Nokia mobile phones via SMS. OTB files contain 1-bit (black and white) images at small fixed resolutions, typically 72x14 pixels for operator logos and 72x28 pixels for group graphics, encoded in a compact binary format suitable for embedding within the payload of SMS text messages. The format uses a simple structure: a header byte indicating whether the image is an operator logo or group graphic, width and height values, and the raw bitmap data where each bit represents one pixel packed eight per byte. The extremely tight format — designed to fit within a single SMS message (140 bytes maximum payload, shared with addressing overhead) — reflects the severe constraints of mobile communication in the late 1990s. Nokia's Smart Messaging system was one of the first commercial implementations of rich content delivery to mobile phones, and OTB images represented the entire visual content capability of Nokia handsets before MMS and mobile data browsing arrived. One advantage is the format's historical role as a pioneer of mobile visual messaging: OTB images were among the first graphics that ordinary consumers could send to each other's phones, predating MMS, camera phones, and smartphones by nearly a decade. The format's minimal footprint is another characteristic — entire images fit in a few dozen bytes, reflecting an era of extreme bandwidth constraints. OTB files are supported by ImageMagick, various Nokia phone management tools, and specialty mobile format utilities.
Developer: Nokia
Initial release: 1997
FB2 (FictionBook) is an XML-based ebook format created by Dmitry Gribov in 2004, designed to provide a clean semantic description of a book's content independent of its visual presentation. Unlike page-layout formats, FB2 encodes structure — title, authors, chapters, annotations, genres, epigraphs, poems, footnotes, and binary attachments (typically cover images) — within a single well-formed XML document. This structural approach means reading applications have full control over rendering, allowing the same file to adapt perfectly to a small phone screen or a large e-ink reader. FB2 became enormously popular in Russia and Eastern Europe, serving as the dominant format on major Russian digital libraries and ebook distribution platforms. One significant advantage is metadata richness: the format's schema mandates detailed bibliographic information including author, translator, series position, publication date, and genre classification, making library management and discovery straightforward. The plain-text XML foundation is another strength — FB2 files are human-readable, easy to validate, and simple to transform using standard XML tools like XSLT. The format specification is freely available on GitHub, and a wide ecosystem of readers, editors, and converters supports it across all major platforms, from desktop applications like Calibre to dedicated e-readers with native FB2 rendering.
Developer: Dmitry Gribov
Initial release: 2004

Frequently Asked Questions

Why would I convert OTB to FB2?

Converting OTB to FB2 packages your images for e-readers. FB2 is an XML-based e-book format popular in Russia, making it suitable for portable reading devices.

What programs open FB2 files?

Open FB2 using FBReader, Calibre, CoolReader, Moon+ Reader. Cross-platform support means you can access these files on virtually any system.

Is OTB to FB2 conversion free?

Standard conversions are available for free on Convertio. Larger volumes or higher usage may benefit from a premium plan for additional capacity.

What platforms support this OTB converter?

Since it runs in the browser, any operating system works — desktop or mobile. No platform-specific software is needed to convert OTB to FB2.

Can I convert multiple OTB files to FB2 at once?

Yes — upload several OTB files in one session and Convertio processes them all into FB2 simultaneously, saving you time.

Does converting OTB to FB2 affect quality?

Quality is maintained to the extent FB2 supports. Since OTB is an Over-The-Air bitmap format for early Nokia phones, the visual data transfers cleanly to FB2.