Rooftop Solar Sizing
Panel count, roof area, generation and payback for a rooftop plant.
Inputs
Results
Enter your values, then press Calculate Now to evaluate the output.
Guide — Rooftop Solar Sizing
The rooftop solar calculator below follows standard Indian construction practice and the relevant IS-code conventions. Enter the site dimensions exactly as measured, press Calculate Now, then refine the quantities line by line in the live sheet before you export.
System size in kilowatt-peak is the daily energy requirement divided by peak sun hours and the system performance ratio, which is typically 0.75–0.80 after inverter, temperature, soiling and wiring losses.
Most of India receives 4.0–5.5 peak sun hours per day averaged annually. A 1 kWp system therefore generates roughly 1400–1600 kWh a year and needs about 9 m² of shade-free roof.
Net metering makes the economics work: exported units offset imported units at the retail tariff. With tariffs above ₹8/kWh, simple payback commonly lands between four and six years against a 25-year panel warranty.
Treat every output as an indicative pre-tender estimate. Site conditions, wastage allowances, specification changes and local market rates all move the final figure, so validate against your drawings and approved rate analysis before procurement.
Master Measurement Sheet
| Sr. No. | Description | Unit | NOS 1 | NOS 2 | L | B | D | QTY | Action |
|---|---|---|---|---|---|---|---|---|---|
| 1 | 1.000 |
Ratings & reviews
What engineers say about the Rooftop Solar Sizing.
Leave a review
Sign in to rate this calculator. Reviews are published after moderation.
About the Rooftop Solar Sizing
This tool is built for site engineers, quantity surveyors, contractors and property investors who need dependable numbers fast. Every input is reactive — changing a single field instantly recomputes the full output set, so you can run sensitivity checks on dimensions, grades and rates before committing to an estimate.
Keep unit consistency in mind: metric inputs (metres, square metres, cubic metres) produce metric outputs, with imperial and Indian trade units shown alongside where they are commonly used on site.