In this article the main characteristics of the web-based eBook Xmath Calculator will be introduced. The Xmath calculator includes different areas of engineering mathematics, Calculus being one of these areas. Xmath Calculator has been developed within the two EU projects Xmath and dMath and includes step-by-step solving for problems given by the user, theory pages written in MathML and streaming lectures for distance education. The calculating unit is written as Mathematica packages (*.m) for webMathematica (*.msp/jsp), including links to MathML theory pages and streaming lectures.