Updated July 2026

Solar Calculator India

Estimate your rooftop solar system size, number of panels, cost after PM Surya Ghar subsidy, monthly generation, savings and payback, customised to your city, electricity bill and usage. No signup, no sales call, just a clear planning estimate.

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Solar System Calculator: Size, Cost & Savings

Get your recommended solar system size, panel count, cost, generation, savings and payback in under a minute.

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Select Your Location

2

Your Electricity Usage

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Estimated consumption: - units/month
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₹
Estimated avg consumption: - units/month
Tip: Checking "Backup" tells the tool to size a battery for that appliance during power cuts (only applies if you select a Hybrid System in Step 3).
Estimated average usage: 0 kWh/month
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System Options

Your Solar Analysis

Results for your location

Why this size?

This recommendation is intended for planning. Final system size may vary based on billing pattern, roof constraints, sanctioned load, and local approval conditions.
System size ≈ Monthly units ÷ (Peak sun hours × 30 × Performance ratio)
Tip: Entering monthly units (kWh) from your electricity bill gives more accurate sizing than entering the bill amount.

Detailed Breakdown

ParameterEstimate
Estimates only, for planning & comparison:
  • Panel count varies with selected brand, roof space, layout and module wattage (~540W to ~620W).
  • Pricing depends on roof type, brand, structure, city and site conditions.
  • Generation varies by city, season, roof direction, shading and installer design.
  • Savings & payback vary with actual tariff, usage pattern, shading and install quality.
  • All figures, including subsidies and savings, are indicative and do not guarantee any specific outcome.

How to Use This Solar Panel Calculator

This tool gives you a quick, planning-level estimate for a rooftop solar system in India. There are three ways to enter your usage, and you can switch between them at any time:

Quick Bill mode

The fastest option. Enter your average monthly electricity bill and the calculator maps it against indicative DISCOM slab tariffs for your city, after deducting estimated fixed charges, to work out your monthly consumption in units (kWh). If you know your monthly units, switch the input type to units for a more accurate result, since bills are distorted by slab jumps and fixed charges.

Seasonal mode

Indian summers push AC and cooler use far above the rest of the year. Seasonal mode lets you enter separate summer and non-summer figures, then sizes a balanced year-round system and flags whether an AC-heavy home needs a larger summer-focused size, so you don't undersize based on a mild winter bill.

Appliance mode

Build your load from scratch. Pick your appliances and quantities and the calculator adds up daily watt-hours and converts them to monthly kWh. Tick "Backup" on the appliances you want running during a power cut and, with a hybrid system selected, the tool sizes a battery for exactly those loads.

Solar System Cost in India by Size (2026)

Indicative gross prices before subsidy, and the central subsidy under the PM Surya Ghar Muft Bijli Yojana that applies to on-grid and hybrid residential systems. Off-grid systems are not eligible for the subsidy. Applications are filed on the official government portal after choosing your system. For a detailed quote-style estimate, use the dedicated solar panel cost calculator, and to see monthly instalments on financing, try the solar loan EMI calculator.

System SizeGross Cost (before subsidy)PM Surya Ghar SubsidyApprox. Net Cost
1 kW₹55,000 – ₹65,000₹30,000₹25,000 – ₹35,000
2 kW₹1,10,000 – ₹1,30,000₹60,000₹50,000 – ₹70,000
3 kW₹1,56,600 – ₹1,91,400₹78,000₹78,600 – ₹1,13,400
5 kW₹2,75,000 – ₹3,25,000₹78,000₹1,97,000 – ₹2,47,000
10 kW₹5,50,000 – ₹6,50,000₹78,000₹4,72,000 – ₹5,72,000

The subsidy is capped at ₹78,000 for systems of 3 kW and above. Some states (Delhi, Uttar Pradesh, Assam and others) add a further top-up. Use the PM Surya Ghar subsidy calculator for your exact figure.

How This Solar Calculator Works

The calculator uses standard, deliberately conservative solar planning maths for Indian homes, with real city-level sun data and DISCOM tariff slabs, so the estimate is grounded rather than optimistic.

System sizing

System size (kW) = Monthly units ÷ (Peak sun hours × 30 × 0.8)

We map peak sun hours by state (central India ~4.8 hrs, Rajasthan ~5.5 hrs, coastal and hill states ~3.8–4.2 hrs) and apply a 0.8 performance ratio to account for dust, wiring, inverter and temperature losses. The result is rounded up to the nearest 0.5 kW.

Panels, roof area and generation

Panels = System watts ÷ module wattage (540W–620W)
Roof area ≈ 80–100 sq. ft. per kW
Monthly generation = System kW × Peak sun hours × 30 × 0.8

You can run each of these numbers on its own tool: the solar panel requirement calculator, the roof area calculator and the solar generation calculator. Every formula used across this site is collected in the solar panel calculation formula guide.

Cost, subsidy and savings

Gross cost uses indicative rates of roughly ₹58,000/kW on-grid, ₹72,000/kW hybrid and ₹85,000/kW off-grid with a ±10% range. The PM Surya Ghar subsidy is modelled as up to ₹30,000 (1 kW), ₹60,000 (2 kW) and ₹78,000 (3 kW and above), and is zeroed for off-grid. Export savings use a conservative ₹3.00/unit planning proxy because net metering policies vary by DISCOM, so payback stays realistic rather than inflated.

Calculation assumptions

  • Performance ratio: 0.8 (real-world atmospheric and inverter losses)
  • Roof area: 80–100 shadow-free sq. ft. per kW
  • Battery: inverter efficiency 85%; lead-acid capped at 50% DoD, lithium at 85% DoD
  • Battery cost: lead-acid ~₹9,000/kWh, lithium ~₹18,000/kWh
  • System cost per kW: on-grid ~₹58,000, hybrid ~₹72,000, off-grid ~₹85,000 (±10%)
  • Export proxy: ₹3.00/unit conservative planning rate for unverified DISCOM policies
  • Tariff escalation: ~5%/year; panel degradation: ~0.5%/year (25-yr projections)
  • EMI: 5-yr @ 9.5% and 7-yr @ 10% (representative)
  • PM Surya Ghar subsidy: up to ₹30,000 / ₹60,000 / ₹78,000 (3 kW+ cap), zeroed for off-grid

Rooftop Solar Calculator for Indian Homes

This tool doubles as a complete rooftop solar calculator for India. It checks whether your roof can host the system you need, using a planning norm of 80 to 100 shadow-free sq. ft. per kW, and then works out what that rooftop solar system will generate, cost and save in your city. Whether you are comparing quotes, planning a subsidy application or simply curious what a rooftop solar power calculator says about your home, the numbers here are grounded in city-level sun data and real DISCOM tariffs.

For deeper dives, use the dedicated solar roof area calculator to check space, the tilt angle calculator to set the right panel angle for your city, and the solar subsidy calculator to confirm your central and state benefit before you sign anything.

Solar Calculator India: Frequently Asked Questions

Your system size depends on monthly consumption: divide your monthly units (kWh) by (peak sun hours × 30 × 0.8). For example, 300 units a month in a city with about 4.8 peak sun hours needs roughly a 2.5–3 kW system. Most Indian homes need between 2 kW and 5 kW. The calculator above sizes it automatically using your city's solar data.
Divide your system size in watts by the panel wattage. Using common 540W–620W modules, a 1 kW system needs about 2 panels, a 3 kW system needs 5–6 panels, and a 5 kW system needs 8–10 panels. Higher-wattage panels reduce the count and save roof space.
Indicative on-grid residential prices are about ₹52,000–64,000 per kW before subsidy. A 3 kW on-grid system costs roughly ₹1.57–1.91 lakh gross; after the PM Surya Ghar subsidy of up to ₹78,000 the net cost drops to about ₹87,000–1.13 lakh. Hybrid and off-grid systems cost more because of batteries.
The PM Surya Ghar (Muft Bijli Yojana) central subsidy for homes is up to ₹30,000 for 1 kW, up to ₹60,000 for 2 kW, and up to ₹78,000 for 3 kW and above. A few states add a top-up. Off-grid systems are not eligible.
Monthly generation = system size (kW) × peak sun hours × 30 × 0.8. A 3 kW system in an area with 4.8 sun hours generates roughly 345 units a month on average. Monsoon months can be 30–40% lower and summer months higher.
After subsidy, payback is typically 3–6 years for most Indian homes. High-tariff states like Maharashtra pay back faster (3–4 years). After payback you get 20+ years of near-free electricity, and savings grow as tariffs rise about 5% a year.
No. On-grid inverters are required to shut down during a grid outage as an anti-islanding safety measure that protects utility line workers. If you need power during outages, you need a hybrid system with battery backup.
Not always. If your grid supply is reliable and you mainly want to cut your bill, an on-grid system without a battery is the cheapest and most efficient choice. If you face frequent power cuts, a hybrid system with a battery sized to your backup appliances makes sense.
Plan for about 80–100 sq. ft. of shadow-free roof per kW. A 1 kW system needs roughly 80–100 sq. ft., a 3 kW system about 240–300 sq. ft., and a 5 kW system about 400–500 sq. ft. South-facing or flat roofs without shading work best.
For most homes with a monthly bill of ₹1,500 or more and reasonable shadow-free roof space, yes. With current subsidy, payback is usually 3–6 years, followed by 20+ years of near-free power. Rising tariffs make the 25-year savings several times the initial investment.

All Free Solar Calculators for India

Purpose-built online solar calculators for every step of going solar: sizing, cost, subsidy, generation, battery backup and system design. Every tool is India-specific, free and works without signup.