MOBI to RGF Converter

Convert MOBI pages to RGF LEGO graphics — free online

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Robotics Display Ready

MOBI to RGF produces images formatted for LEGO Mindstorms EV3 screens — turn ebook artwork into custom graphics for your robot projects.

Browser-Only Workflow

No EV3 software needed for the conversion step. Use any web browser to convert MOBI to RGF, then transfer the file to your EV3 brick.

Files Stay Safe

MOBI uploads are deleted immediately after conversion. RGF output is erased from servers within 24 hours — nothing is kept long-term.

How to convert MOBI to RGF

1

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

2

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

3

Let the file convert and you can download your rgf 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
RGF (Robot Graphics Format) is a simple monochrome bitmap image format used by LEGO Mindstorms EV3 programmable robotics kits, introduced with the EV3 system on September 1, 2013. RGF files store 1-bit (black and white) images designed for display on the EV3 Intelligent Brick's 178x128 pixel monochrome LCD screen. The format uses a minimal structure: a header containing the image width and height as binary values, followed by the pixel data where each bit represents one pixel (1 for black, 0 for white), packed eight per byte in row-major order. RGF images are used as custom display graphics in EV3 programs — students and hobbyists create them for robot status displays, user interfaces, splash screens, and animation frames shown on the brick's screen during program execution. The images are typically designed using LEGO's EV3 software (which includes a built-in image editor) or converted from other formats using community tools. RGF fits within LEGO's broader educational robotics platform, where the Mindstorms system teaches programming, engineering, and computational thinking to students worldwide. One advantage is the format's role in educational technology: RGF provides a simple, concrete example of how digital images are represented as binary data — a concept that students working with Mindstorms can directly observe by examining the file contents and seeing the corresponding image on the brick's screen. The format's simplicity makes it accessible for young programmers learning about file formats and binary data. RGF files can be created and converted using ImageMagick, the EV3 development environment, and community tools like ev3dev.
Developer: The LEGO Group
Initial release: 2013

Frequently Asked Questions

Why convert MOBI to RGF?

RGF images display on LEGO Mindstorms EV3 screens — converting MOBI pages lets you show ebook snippets or artwork on your EV3 robot display.

What uses RGF files?

LEGO Mindstorms EV3 programming environments use RGF images. The EV3 brick itself displays RGF files on its built-in monochrome LCD screen.

What resolution is the EV3 screen?

The EV3 brick has a 178x128 pixel monochrome display. RGF images are typically sized to fit within these compact screen dimensions.

Will ebook text be readable in RGF?

Due to the small resolution, full pages will not be readable as text. RGF is better suited for cover art, icons, or simple graphic snippets.

Is the service free?

Yes — MOBI to RGF conversion is free on Convertio. Premium plans offer additional features like bigger file sizes and faster processing.