> For the complete documentation index, see [llms.txt](https://docs.k9rockettech.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.k9rockettech.com/design-and-simulation/ecalc.md).

# eCalc

eCalc is the ultimate UAV design and simulation tool for optimizing the efficiency and power performance of your vehicle. It's also a very good starting point for designing your drone. It is a paid software for its full features, but well worth the $19 dollars a year. 

{% embed url="<https://www.ecalc.ch/>" %}