Home & Energy Calculators
Get a grip on your power bill — estimate electricity costs, AC running and solar savings.
Updated June 2026 · Free · No sign-up
Electricity is one of the steadiest household expenses in India, and a few choices around your air conditioner and rooftop can swing the bill by thousands of rupees a year. This cluster helps you understand and trim those costs, starting with the Electricity Bill calculator that applies the slab tariffs of major state discoms like MSEDCL, BESCOM, TNEB and BSES, complete with fixed charges, electricity duty and GST. From there you can dig into the appliances that drive the bill.
Air conditioning is usually the biggest single load in an Indian home, so the AC Electricity Cost and AC Tonnage calculators help you pick the right size and star rating and see how quickly a 5-star unit pays back over a 3-star one. If you are weighing up a rooftop system, the Solar ROI and PM Surya Ghar Subsidy calculators factor in the Central Financial Assistance under the PM Surya Ghar Muft Bijli Yojana to show your real payback period. Comfort and weather tools like Heat Index and Dew Point round out the cluster.
All Home & Energy Calculators
Electricity Bill Calculator
Calculate monthly electricity bill across 8 major state discoms (MSEDCL Maharashtra / BESCOM Karnataka / TNEB Tamil Nadu / BSES Delhi / KSEB Kerala / UPPCL UP / TSSPDCL Telangana / APSPDCL Andhra). Applies state-specific slab tariff structure + fixed charges + electricity duty + GST.
AC Electricity Cost Calculator
Calculate monthly AC running cost from tonnage (0.75T / 1T / 1.5T / 2T), ISEER star rating (1-5 star), daily usage hours, and your state's electricity tariff. Compares 3-star vs 5-star payback period.
AC Tonnage Calculator
Calculate required AC tonnage based on room size (sqft), ceiling height, climate zone (hot / very hot), sun exposure, occupants, and appliances. Returns 0.75 / 1 / 1.5 / 2 / 2+ ton recommendation with reasoning.
Solar ROI Calculator
Calculate solar rooftop installation ROI with PM Surya Ghar subsidy (₹30K-78K for 1-3kW, max ₹78K for 3-10kW), state-specific tariff, monthly bill savings, and 25-year payback. Supports kW capacity from 1-10kW residential.
BTU / AC Size Calculator
Calculate the BTU needed to heat or cool a room based on square footage and conditions.
Heat Index Calculator
Calculate heat index (feels-like temperature) from air temperature and relative humidity.
Dew Point Calculator
Calculate dew point temperature from air temperature and relative humidity.
PM Surya Ghar Subsidy Calculator
Calculate Central Financial Assistance (CFA) subsidy under the PM Surya Ghar Muft Bijli Yojana — ₹30,000 for 1kW, ₹60,000 for 2kW, ₹78,000 cap for 3kW+. Direct-bank-transfer post-installation by a DISCOM-empanelled vendor.
Frequently asked questions
How is a residential electricity bill calculated in India?
Most state discoms use a telescopic slab tariff, where each block of units consumed is charged at a progressively higher rate. On top of the energy charge, the bill adds a fixed charge based on your sanctioned load, an electricity duty levied by the state, and applicable taxes. Because slab rates and duties differ by discom, the bill for the same units varies from state to state.
Does a 5-star AC really save money over a 3-star?
Yes. A higher ISEER star rating means the AC consumes less electricity to deliver the same cooling, so a 5-star unit uses noticeably fewer units per hour than a 3-star one. The upfront price is higher, but for households that run the AC for many hours a day, the lower running cost typically pays back the difference within a few seasons. The AC Electricity Cost calculator estimates this payback for your usage.
What is the PM Surya Ghar subsidy for rooftop solar?
Under the PM Surya Ghar Muft Bijli Yojana, the central government provides a fixed Central Financial Assistance for residential rooftop solar — around Rs 30,000 for 1 kW, Rs 60,000 for 2 kW, and a cap of Rs 78,000 for systems of 3 kW and above. The subsidy is paid by direct bank transfer after installation by a DISCOM-empanelled vendor. The Solar ROI and PM Surya Ghar Subsidy calculators factor this into your payback.
What AC tonnage do I need for my room?
Tonnage depends mainly on room size, but ceiling height, climate, sun exposure, the number of occupants and heat-generating appliances all matter. As a rough guide, a small bedroom often needs around 1 ton while a larger living room may need 1.5 to 2 tons, with hotter cities and sun-facing rooms pushing the requirement higher. The AC Tonnage calculator weighs all these factors to suggest a size with reasoning.
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