Electricity Cost Calculator
The electricity cost calculator estimates your monthly bill by adding up the energy consumption of each appliance in your home. Enter the wattage, hours of daily use, and days per month for each appliance, set the rate per kWh (default ₹8 for India), and the calculator shows the monthly cost for each item and the total. The bar chart reveals which appliances cost the most.
How to Use
- Keep the default electricity rate of ₹8 per kWh or enter the rate from your electricity bill.
- Review the preloaded appliances and edit wattage, daily hours, and days per month to match your home.
- Use Add Appliance for additional devices such as geysers, pumps, routers, ovens, or desktop computers.
- Click Calculate Electricity Cost to see monthly kWh, cost per appliance, total monthly units, monthly bill estimate, and annual cost.
- Read the horizontal bar chart to identify which appliances contribute the most to your monthly electricity cost.
Electricity Cost Formula
Cost = kWh x electricity rate
Annual cost = monthly cost x 12
Electricity bills are based on energy, not just power. Watts measure how quickly an appliance uses energy at a moment in time. Kilowatt-hours measure total energy over time. A 1000 W appliance running for one hour uses 1 kWh, often called one unit of electricity in India. A 100 W television running for 10 hours also uses 1 kWh. The calculator divides watts by 1000 to convert to kilowatts, multiplies by hours per day and days per month, then multiplies by your rate per kWh.
The result is an estimate because real appliances do not always draw their nameplate wattage continuously. Refrigerators cycle on and off. Inverter air conditioners vary compressor speed. Washing machines use different power during wash, spin, and heating phases. A geyser may run at high wattage but only until the thermostat cuts off. Still, the formula is the correct starting point and is accurate enough for comparing usage patterns, identifying expensive appliances, and estimating savings from reduced hours or more efficient equipment.
Worked Example
A 1.5 ton air conditioner rated at 1500 W runs 8 hours per day for 25 days. Monthly kWh = (1500 / 1000) x 8 x 25 = 300 kWh. At ₹8 per kWh, monthly cost = 300 x 8 = ₹2,400. Annualized over 12 similar months, that usage would cost ₹28,800.
A ceiling fan rated at 75 W running 12 hours daily for 30 days uses (75 / 1000) x 12 x 30 = 27 kWh. At the same rate, cost is 27 x 8 = ₹216 per month. The fan runs more hours, but the AC costs far more because its wattage is much higher. This is why high-wattage cooling and heating appliances dominate many household bills.
Wattage of Common Indian Household Appliances
| Appliance | Typical wattage | Category |
|---|---|---|
| LED bulb | 7-15 W | Lighting |
| Ceiling fan | 65-80 W | Cooling |
| Table fan | 25-50 W | Cooling |
| Air cooler | 150-200 W | Cooling |
| Split AC (1 ton) | 1000 W | Cooling |
| Split AC (1.5 ton) | 1500 W | Cooling |
| Refrigerator | 100-200 W | Kitchen |
| Microwave | 800-1200 W | Kitchen |
| Electric kettle | 1500 W | Kitchen |
| Geyser (water heater) | 2000-3000 W | Bathroom |
| Washing machine | 350-500 W | Laundry |
| Television (32" LED) | 50 W | Entertainment |
| Television (55" LED) | 120 W | Entertainment |
| Laptop | 45-65 W | Electronics |
| Desktop computer | 150-300 W | Electronics |
Finding the Biggest Electricity Costs
The most expensive appliance is not always the one used for the longest time. Cost depends on wattage multiplied by hours. A Wi-Fi router may run all day, but at 10 W it uses only about 7.2 kWh in a month. A geyser may run for one hour a day, but at 2500 W it uses 75 kWh in a month. Air conditioners, water heaters, electric kettles, irons, ovens, pumps, and older refrigerators often deserve the first check because they combine meaningful wattage with regular use.
Electricity rates can also be slab-based. Some Indian residential bills charge a lower rate for initial units and higher rates after a threshold, with fixed charges and taxes added. This calculator uses one average rate per kWh because it is clearer for appliance comparison. For bill reconciliation, divide your total energy charge by billed units to estimate an average rate, then enter that number. If solar generation, time-of-day pricing, or prepaid meters apply, use the rate that best represents the units consumed by the appliances you are comparing.
FAQ
How is electricity bill calculated in India?
Indian electricity bills usually charge for units consumed, where one unit equals one kWh. The bill may include energy charges based on slabs, fixed charges, meter rent, fuel adjustment charges, taxes, and other local components. Residential rates differ by state, distribution company, sanctioned load, and consumption band. This calculator estimates the energy portion by multiplying appliance kWh by an average rate. For exact billing, read your tariff schedule and bill line items. For appliance comparison, an average per-unit rate is often enough.
What uses the most electricity at home?
High-wattage cooling and heating appliances usually use the most electricity. Air conditioners, geysers, room heaters, electric ovens, pumps, old refrigerators, and clothes dryers can dominate a bill. Usage hours matter too. A lower-wattage device used continuously can still add up, but high-wattage appliances create the biggest monthly changes when usage increases. The chart on this page helps identify your top contributors. After finding them, reduce run hours, improve insulation, service equipment, choose efficient settings, or replace inefficient appliances when the payback makes sense.
How many units does an AC use per hour?
An AC's hourly units depend on its power draw. A 1.5 ton AC drawing about 1500 W uses roughly 1.5 kWh per hour if running at that level continuously. Inverter models may use less after the room reaches the set temperature, while older or poorly maintained units may use more. Room size, insulation, outdoor temperature, thermostat setting, sunlight, and filter condition all matter. As a rough estimate, units per hour = watts / 1000. For better accuracy, use a plug-in energy meter or smart meter data.
How do I reduce my electricity bill?
Start with the largest contributors. Set AC temperatures moderately, clean filters, seal air leaks, use fans to improve comfort, reduce geyser runtime, switch to LED lighting, run washing machines with full loads, and turn off standby devices that are not needed. Maintain refrigerators with good door seals and ventilation. Compare old appliances with star-rated efficient models before replacing them; savings are highest when usage is heavy. Track monthly units after changes so you can separate real savings from weather or occupancy differences.
What is a unit of electricity (kWh)?
A unit of electricity is commonly one kilowatt-hour, abbreviated kWh. It means using one kilowatt of power for one hour. A 1000 W geyser running for one hour uses 1 kWh. A 100 W bulb running for ten hours also uses 1 kWh. Electricity meters record energy in these units, and bills multiply units by the applicable tariff. Understanding kWh helps compare appliances fairly because both wattage and runtime are included. Watts alone do not tell the full cost.