MOBI to RB Converter

Convert MOBI ebooks to RB format — free online tool

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Retro Reader Support

Move MOBI ebooks to the RB format — bridging modern Kindle content with the pioneering Rocket eBook hardware from the dawn of e-reading.

Web-Based Conversion

No obscure desktop tools needed to produce RB files. Convertio handles this niche conversion entirely in your browser.

Files Deleted Promptly

Uploaded MOBI ebooks are removed immediately after processing. Converted RB files are purged from servers within 24 hours.

How to convert MOBI to RB

1

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

2

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

3

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

About formats

MOBI is an ebook format originally developed by Mobipocket SA, a French company founded in 2000 that was later acquired by Amazon in 2005. The format builds on the PalmDOC/PDB container structure, adding support for HTML-based content markup, embedded images, a DRM layer, and a JavaScript subset for limited interactivity. MOBI files use a record-based database architecture inherited from Palm OS, with a header structure containing metadata like title, author, publisher, and language followed by compressed HTML content records. The format became the foundation of Amazon's early Kindle ecosystem — the original AZW format used on first-generation Kindles was essentially MOBI with Amazon's own DRM wrapper. MOBI supports reflowable text with basic formatting including bold, italic, headings, lists, and tables, as well as internal hyperlinks and a built-in table of contents. One advantage is broad device compatibility: MOBI files are recognized by Kindle devices and apps spanning over a decade of hardware, as well as numerous third-party readers on desktop and mobile platforms. The format's lightweight structure is another strength — even long novels produce compact files that load quickly on modest hardware. While Amazon has since moved to the more capable AZW3/KF8 format for new publishing, MOBI remains widely circulated in existing ebook libraries and continues to be produced by conversion tools like Calibre for maximum Kindle compatibility.
Developer: Mobipocket SA
Initial release: 2000
RB is the native ebook format of the Rocket eBook, one of the first commercially available dedicated e-reading devices, developed by NuvoMedia and released in October 1998. Founded by Martin Eberhard and Marc Tarpenning — who later co-founded Tesla Motors — NuvoMedia designed the Rocket eBook as a handheld device with a reflective LCD screen, capable of storing approximately ten books in its internal memory. The RB format packages HTML-based content along with embedded images, metadata, and a table of contents into a single binary container optimized for the device's limited hardware. Content was purchased and downloaded through NuvoMedia's RocketLibrarian desktop software. A notable advantage of the format was its early support for bookmarking, annotation, dictionary lookups, and adjustable font sizing — features now standard on modern e-readers but revolutionary in the late 1990s. The Rocket eBook demonstrated viable commercial demand for dedicated reading devices, paving the way for subsequent platforms from Sony, Amazon, and others. NuvoMedia was acquired by Gemstar-TV Guide International in 2000, which discontinued the device line in 2003. While RB files are largely a historical curiosity today, they can be converted to modern formats using ebook management tools, and the format remains significant as a pioneering chapter in the evolution of digital reading.
Developer: NuvoMedia
Initial release: 1998

Frequently Asked Questions

Why convert MOBI to RB?

RB is the native format for Rocket eBook — one of the earliest dedicated e-readers. Converting MOBI lets you read on this classic device.

How do I open an RB file?

The Rocket eBook (REB 1100/1200) reads RB natively. On modern computers, Calibre can open, view, and further convert RB ebook files.

Is RB still in active use?

RB is a vintage format from the late 1990s. It serves collectors and enthusiasts who maintain Rocket eBook devices for nostalgic or archival use.

Does the conversion keep basic text formatting?

Core text content and paragraph structure transfer from MOBI to RB. Advanced formatting may simplify given the limitations of the RB format.

How long does MOBI to RB conversion take?

Typically a few seconds — Convertio processes ebook conversions quickly on its servers regardless of the age or rarity of the target format.

MOBI to RB Quality Rating

4.9 (7 votes)
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