Solar Panel Size Calculator — How Many Panels Do You Need? Solar Panel Size CalculatorMonthly Electricity Usage (kWh)Your StateAlabamaAlaskaArizonaArkansasCaliforniaColoradoConnecticutDelawareFloridaGeorgiaHawaiiIdahoIllinoisIndianaIowaKansasKentuckyLouisianaMaineMarylandMassachusettsMichiganMinnesotaMississippiMissouriMontanaNebraskaNevadaNew HampshireNew JerseyNew MexicoNew YorkNorth CarolinaNorth DakotaOhioOklahomaOregonPennsylvaniaRhode IslandSouth CarolinaSouth DakotaTennesseeTexasUtahVermontVirginiaWashingtonWest VirginiaWisconsinWyomingRoof EfficiencyNo shading (100%)Minimal (90%)Some shading (80%)Heavy shading (70%)Calculate Panel NeedsYour Solar Panel RequirementsSystem Size Needed--Number of 400W Panels--Roof Space Required--Daily Production--Annual Production--Get sized solar quotes. Free Solar Quotes Scroll to Top