Drake equation: How many alien civilizations exist?

This interactive calculator that takes the Drake equation to the next level: It not only shows the variables that are taken into account in Drake's equation, but also allows the user to test the lowest estimated values, today's optimistic estimate, today's skeptical estimate, or simply use the values he/she wants. using these values, the system then calculates the estimated number of civilizations in our galaxy and the this number multiplied by the estimated number os galaxies in the visible universe, in order to present the number of communicating civilizations in the universe.