Solar and EV calculators

Every calculator on WattDekho starts from numbers you already have, usually your electricity bill, and shows the working behind each result. Nothing asks for your phone number.

Home solar

Solar calculator

System size, cost after subsidy and payback from your bill.

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PM Surya Ghar subsidy

Central subsidy for homes and housing societies, by state.

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Solar EMI

Loan EMI at 2026 bank rates, and whether the saving covers it.

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Plan the system

Units generated

Units a day, month and year for any size, in your state.

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Roof area

How many kW and panels your roof can hold.

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Home load

Add up appliances to get your load and monthly units.

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Power and backup

Electricity units

Convert watts and hours into units (kWh) and rupees.

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Inverter battery backup

How long a battery runs your load, and the inverter size.

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EV running cost

Electric vs petrol per km and per month.

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For businesses

Solar park (open access)

Your real price per unit after grid fees, by state.

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Rooftop: buy or pay per unit

CAPEX vs RESCO over 25 years, with tax benefit.

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State open access fees

Wheeling, cross-subsidy and banking charges we have verified.

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Every formula and source is listed on how we calculate.