Optimum Light Calculator   Q. How many lights do I need in my room? A. For optimum lumens, you should have 20 (min) to 60 (max) watts per square foot.   All values must be entered to obtain results.   Total Number of Lights Lights = Wattage per Light Watts = Length of room (ft.) Length = Width of room (ft.) Width = Results Total wattage requirement per square foot Watts/Sq. Ft. =