calcWIND Lite is an educational tool that assembles four different, stand-alone formulas that estimate a wind turbine’s annual output. They work simultaneously in feet and MPH and in meters and m/s to link rotor size (2 to 250 feet) and wind speed (1 MPH to the top end of Class 7) to energy (kW-hrs). All are over-simplifications – if you don't like the weather, wait ten minutes! The four methods do not necessarily agree, nor are they intended to predict outputs at any given site or set of conditions.