  We have developed a comprehensive methodology and an interactive website for
calculating the habitable zone (HZ) of multiple star systems. Using the concept
of spectral weight factor, as introduced in our previous studies of the
calculations of HZ in and around binary star systems, we calculate the
contribution of each star (based on its spectral energy distribution) to the
total flux received at the top of the atmosphere of an Earth-like planet, and
use the models of the HZ of the Sun to determine the boundaries of the HZ in
multiple star systems. Our interactive website for carrying out these
calculations is publicly available at http://astro.twam.info/hz . We discuss
the details of our methodology and present its application to some of the
multiple star systems detected by the Kepler space telescope. We also present
the instructions for using our interactive website, and demonstrate its
capabilities by calculating the HZ for two interesting analytical solutions of
the three-body problem.
