RB to CUR Converter

Convert Rocket eBook to CUR cursors — free, online

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Custom Cursors

Extract imagery from RB ebook files and package it into CUR format — ready for use as a custom Windows cursor.

Near-Instant Speed

CUR files are small and simple, so the entire RB to CUR conversion pipeline completes in just seconds.

Automatic Deletion

RB uploads are erased right after processing finishes. CUR downloads are removed from servers within 24 hours.

How to convert RB to CUR

1

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

2

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

3

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

About formats

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
CUR is the cursor image format for Microsoft Windows, structurally nearly identical to the ICO (icon) format but with the addition of a hotspot coordinate that identifies the precise pixel position where mouse clicks register. Introduced with early Windows versions, CUR files use the same container structure as ICO: a directory header listing one or more image entries, each specifying dimensions and color depth, followed by the pixel data for each variant. Like ICO, a single CUR file can contain multiple images at different sizes and color depths, allowing Windows to select the most appropriate cursor image for the current display resolution and color settings. Image data within CUR files can be stored as BMP pixel arrays (for legacy compatibility) or as embedded PNG images (supported since Windows Vista) for alpha-blended cursors with smooth edges. The hotspot coordinate — the distinguishing feature separating CUR from ICO — is stored as an X,Y pair in the directory entry header, typically pointing to the tip of an arrow or the center of a crosshair. One advantage is multi-resolution packaging: a single CUR file provides appropriate cursor imagery across display densities from standard DPI to high-DPI screens. Native Windows integration is another strength — CUR files are loaded directly by the operating system for mouse cursor display without any third-party software. CUR files are used by application developers and theme creators to customize the pointing experience across Windows environments.
Developer: Microsoft
Initial release: 1987

Frequently Asked Questions

Why convert RB to CUR?

RB is a dead ebook format. CUR conversion lets you extract page imagery to use as custom Windows cursor graphics.

What uses CUR files?

Windows uses CUR for mouse cursors. Developers and theme creators use CUR files to build custom cursor packages.

How is CUR different from ICO?

CUR includes hotspot coordinates that define the active click point. Otherwise it shares the same image container as ICO.

Does the conversion take long?

Not at all — CUR files are tiny, so conversion finishes almost instantly on Convertio servers.

Is RB to CUR free?

Yes, Convertio offers RB to CUR conversion at no charge. Premium plans unlock batch conversion and higher file limits.