Solar Panel Count & Inverter Sizing

Our Solar Panel Count & Inverter Sizing Calculator helps homeowners, contractors, and energy planners determine the right number of panels and matching inverter size. With inputs for roof space, irradiance, and efficiency losses, it provides accurate, optimized results to support reliable solar energy system design, better planning, and maximum return on investment.


1) Project & Site
Units: meters, kW, °C
2) Module & Inverter

3) Roof Facets & Layout
Add one or more rectangular facets. Layout packs modules with setbacks and spacing; obstruction area is subtracted.
FacetW (m)H (m)Tilt°Az°Setback (m)Spacing (m)OrientationObstruction m²
4) Irradiance, Temperatures & Losses
Monthly POA irradiance (kWh/m²) and ambient temperature (°C). Soiling loss per month (%).
MonthPOA (kWh/m²)Ambient °CSoiling %
Roof Layout Visualizer
Scale 1:1
Each facet is drawn to scale relative to others. Blue rectangles = modules. Gray = obstructions (area approximation).
Total Modules
kWdc
Recommended inverter(s):
Annual kWh (AC)
DC/AC
Clipping est.:
String Sizing & MPPT Assignment
CheckValue
Monthly Energy (AC)
MonthPOATemp °CSoiling %kWh
Loss Waterfall (Annual)
Details & Assumptions
  • Temperature model uses NOCT estimate: Tcell = Tamb + (NOCT − 20)/800 × POA; power derate via γP (Pmax %/°C).
  • String checks: cold Voc against inverter Max DC; hot Vmp against MPPT min; strings/MPPT against current limit.
  • Irradiance-to-energy: simple PR model. For precise results use hourly data; clipping estimate heuristic when DC/AC > 1.

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Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.