Solar planning tools
Solar calculators
Move from energy use to equipment and cost with one connected set of transparent planning tools. Every calculator keeps its inputs, assumptions, and sources visible.
Planning stage
Solar system sizing
Turn energy use into array, panel-count, off-grid, or RV planning estimates.
How Many Solar Panels Do I Need CalculatorEstimate solar system size, panel count, annual production, and roof area from energy use, ZIP, panel watts, orientation, and shading.Solar System Size CalculatorEstimate required solar array kW and annual production from monthly energy use, ZIP, orientation, shading, and visible loss assumptions.Off-Grid Solar CalculatorAggregate daily loads to estimate off-grid solar array power, battery storage, bank amp-hours, and charge-controller current.RV Solar CalculatorEstimate an RV solar array, battery storage, bank amp-hours, and controller current from an editable list of travel loads.
Planning stage
Solar equipment
Plan storage, controller, inverter, cable-loss, angle, and portable-power requirements.
Solar Battery CalculatorEstimate solar battery energy, amp-hours, autonomy, and a series-parallel unit count from daily use and visible storage assumptions.Battery Bank CalculatorCalculate series/parallel battery quantity, bank voltage, amp-hours, and watt-hours from unit specifications.Solar Charge Controller CalculatorCalculate minimum controller charge current and cold-weather PV input voltage from array watts, panel Voc, series count, temperature, and bank voltage.Inverter Size CalculatorAggregate running and surge loads, then apply your own headroom and efficiency assumptions.Solar Cable Voltage Drop CalculatorCalculate resistive DC voltage drop and cable power loss between solar-system components.Solar Panel Angle CalculatorEstimate a fixed or seasonal solar-panel tilt from latitude and compare the direct-beam geometry at an entered installation angle.Portable Power Station CalculatorEstimate portable power-station capacity, runtime, and recharge time from an AC load, daily hours, trip length, usable efficiency, and charging input.
Planning stage
Solar economics
Compare visible production, rate, cost, financing, and ownership assumptions.
Solar ROI CalculatorEstimate solar production first, then show dated simple ROI, payback, and net savings from visible cost, rate, escalation, and degradation inputs.Solar Savings CalculatorEstimate annual solar production, first-year bill offset, and long-term simple savings from visible usage, system, rate, and degradation inputs.Solar Payback CalculatorEstimate solar production independently, then calculate simple payback from visible installed cost, energy use, rate, escalation, and degradation.Solar Loan CalculatorEstimate a solar loan payment, dealer-fee-adjusted principal, total payments, bill comparison, and an optional verified principal lump sum.Solar Lease vs Buy CalculatorCompare nominal 25-year cash, loan, lease, PPA, and utility-baseline payments from visible user assumptions.Commercial Solar CalculatorEstimate commercial solar production, first-year energy value, operating value, and an optional user-confirmed MACRS depreciation scenario.