Simply select your room type, put in your measurements, and decide how much light (or illumination) you need in that space. Finally, select between light or dark interior and the location you will be placing your light sources. Viola! The table below the calculator will show both the lumens and wattage required for your room. It's best practice to go a little over the estimate when shopping for lights as LED's do lose brightness over time and even burn out. If you're shopping for LED fixtures, it's better to go off of the lumens rather than wattage as efficacy ranges between manufacturers and models.