About SolarPanelCalculator.org
Free + Fast + Transparent + Unbiased + Practical Solar Calculations
Why We Built This Site
Most online solar calculators are not engineering tools—they are thin lead-generation funnels designed to collect your phone number and sell it to high-pressure contractors. We believe homeowners, engineers, and off-grid builders deserve immediate, transparent mathematical models without gatekeeping.
Engineering Standards Compliance
Our sizing formulas are built around the National Renewable Energy Laboratory (NREL) PVWatts performance models and International Electrotechnical Commission (IEC) 61724 standards. We openly disclose all derate factors, inverter clipping ratios, and seasonal solar irradiance assumptions.
Zero Commercial Affiliation
SolarPanelCalculator.org maintains no commercial affiliation with any solar manufacturer, installer network, or financing entity. Our recommendations prioritize the user's objective financial return and technical feasibility above all else.