SOLAR ENGINEERING & ASSESSMENT TOOLS
Open Solar Calculators, for Everyone
Eight calculators spanning savings estimates to string voltages, battery banks, and ground-mount row spacing — the standard math the industry runs daily, documented and free in your browser.
No sign-up · No email · Results computed instantly on your device
Assessment & Financial
PM Surya Ghar Subsidy CalculatorCentral + state subsidy, net cost and payback for your homeSolar ROI EstimatorSystem size, savings & payback from your bill and roof areaEnergy Yield EstimatorAnnual kWh generation & specific yield (PVWatts-style check)CAPEX vs RESCO CalculatorOwn vs zero-investment PPA — IRR, NPV & 25-year cashflow
Engineering & Electrical
Panel Tilt & Azimuth OptimizerOptimal module angle for your site coordinatesString SizerSafe min/max modules per series stringInverter DC/AC Ratio CheckerMatch inverter to array & avoid clipping lossesDC Cable SizerCopper cross-section for <2% voltage dropBattery Backup SizerBank capacity, Ah & unit count for outage backupInter-Row Spacing (GCR) CalculatorShadow-free row pitch for ground-mount & flat roofs