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Both calculators run independently — change the inputs on either side to compare results.

Solar Panel System Sizing Calculator

Size a rooftop solar PV system from your real electricity usage, local peak sun hours, system losses, and your target offset — and get the number of panels you actually need.

Average monthly electricity use (kWh)

Peak sun hours (daily average) (h/day)

Share of usage to offset (%)

System losses (inverter, wiring, soiling, heat) (%)

Panel power rating (W)

Solar Energy

Solar Panel Output Calculator

Calculate the daily energy output (kWh) of a solar panel from its rated wattage, daily peak-sun hours, and efficiency. Use it during system sizing or to estimate production from a specific panel under your local sunlight conditions.

Panel Wattage (W)

Peak Sun Hours (hours)

System Efficiency (%)

Key differences

	Solar Panel System Sizing Calculator	Solar Panel Output Calculator
Category	Solar Energy	Solar Energy
Inputs required	5	3
Result	Solar panels needed (panels)	Daily Energy Output (kWh)
What it does	Size a rooftop solar PV system from your real electricity usage, local peak sun hours, system losses, and your target offset — and get the number of panels you actually need.	Calculate the daily energy output (kWh) of a solar panel from its rated wattage, daily peak-sun hours, and efficiency. Use it during system sizing or to estimate production from a specific panel under your local sunlight conditions.