Solar Panel Calculator
Calculate solar panel requirements based on your electricity consumption and roof space
Electricity Consumption
System Configuration
System Requirements
Space Requirements
Cost Estimate
Energy Analysis
System Overview
How Solar Panel Calculation Works
Consumption Analysis
Monthly consumption = Bill amount ÷ Electricity rate = ₹3,000 ÷ ₹6/kWh = 500 kWh
System Sizing
System size = Daily consumption ÷ (Sunlight hours × Efficiency) = 16.67 ÷ (5 × 80%) = 4.17 kW
Space & Cost
Roof area = Number of panels × Area per panel = 8 × 21 sq ft = 168 sq ft
Energy Generation
Daily generation = System size × Sunlight hours × Efficiency = 4.17 kW × 5h × 80% = 16.68 kWh/day
Solar Panel Technology Comparison
Panel Efficiency:
- • 330W: Standard efficiency, lower cost
- • 445W: High efficiency, good value
- • 540W: Premium efficiency, space-saving
- • 665W: Latest technology, maximum power
System Optimization:
- • Higher wattage panels = fewer panels needed
- • Less roof space required with efficient panels
- • Consider shading and roof orientation
- • Factor in local sunlight hours and weather
Your System Recommendation:
The Solar Panel Calculator is for homeowners deciding how big a rooftop solar system they need. Based on your monthly electricity bill, local sunlight hours and panel wattage, it estimates the system size, number of panels, roof area required, and approximate cost.
Solar Panel Calculator - FAQs
How do you calculate the solar system size I need?
System size (kW) = daily electricity consumption ÷ (peak sunlight hours × system efficiency). Daily consumption is derived from your monthly bill divided by your electricity rate, then divided by 30.
How many panels will I need?
Number of panels = required system size ÷ individual panel wattage, rounded up. Roof area is estimated at about 21 sq ft per panel for a 540W panel.
Does higher panel wattage mean fewer panels?
Yes — higher-wattage panels (445W-665W) generate more power per panel, so you need fewer panels and less roof area to reach the same system size, though they typically cost slightly more per panel.
What does "system efficiency" account for?
It reflects real-world losses from inverter conversion, wiring, dust, shading and temperature — typically 70-90% of the panels' rated output reaches usable electricity.
Are panel prices and sunlight-hour assumptions accurate for my exact location?
They are reasonable India-wide averages. Actual sunlight hours vary by city and season, and panel prices vary by brand, so treat results as an estimate rather than a final quote.
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