Professional Solar Sizing, Free Forever
Solar Calculator Pros gives you 15 engineering-grade calculators for designing photovoltaic systems — from total load analysis and battery bank sizing to payback and ROI. Every formula is referenced against IEEE, NEC, IEC, NREL, and SEIA standards. No signup. No uploads. Your projects stay in your browser.
Core Sizing Calculators
Total Load CalculatorDaily energy consumption and peak power from an 80+ appliance database.
Battery Bank SizerAh and kWh sizing with correct DoD and autonomy formulas.
Solar Panels NeededPanel count from daily Wh, peak sun hours, and system losses.
Charge Controller SizerMPPT amperage with NEC 125% safety margins.
Inverter SizingContinuous and surge-rated inverter selection.
Performance & Optimization
Panel Tilt & OrientationOptimal angle and azimuth for your latitude.
Rooftop Layout PlannerVisualize panel fit with rail spacing and setbacks.
Annual Energy ProductionYearly kWh forecast with degradation curves.
Battery Charge TimeTime-to-full from your solar array.
Cable Gauge (AWG)NEC 690.8 compliant wire sizing with voltage drop.
Sunlight Hours & LocationPeak sun hours for 200+ global cities.
What Can My Panels Power?Real-world appliance compatibility check.
Financial & Advisor
Payback & ROI EstimatorBreak-even and 25-year return with compounding inflation and degradation.
Basic System Cost EstimatorBallpark equipment and installation costs.
Solar Journey KickstarterGuided calculator sequences for off-grid, backup, RV, and grid-tied goals.
Projects & Reports
Save any calculator's output to a project (up to 3 projects), drag cards to organize them on a preview canvas, and export a branded PDF report for your records or clients. Download, share, or print directly from the browser.
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