Electricity Cost Calculator

Electricity Cost Calculator

What this calculator does

Ever wondered how much that air conditioner, geyser, or refrigerator actually adds to your electricity bill? This calculator turns an appliance's power rating into money. You enter:

• the appliance's power rating (in watts or kilowatts - check the label or manual)
• how many of that appliance you run
• how many hours per day it runs
• your electricity tariff (the price you pay per kWh, also called per unit)

It then shows the energy consumed and what it costs you per day, week, month, and year - so you can see at a glance which appliances are quietly driving your bill up.

Formula Used

Electricity is billed in kilowatt-hours (kWh), often called "units" on your bill. One kWh is 1,000 watts running for one hour.

$$E_{daily} = \frac{P_{watts} \times H \times N}{1000}$$ $$Cost = E_{kWh} \times Tariff$$

Where:

• P_watts = power rating of the appliance in watts (1 kW = 1,000 W)
• H = hours the appliance runs per day
• N = number of identical appliances
• E_daily = energy consumed per day in kWh
• Tariff = your electricity price per kWh

Weekly, monthly, and yearly figures scale the daily energy by 7, 30, and 365 days respectively.

How to use it

1. Find the power rating on the appliance's label, nameplate, or manual. It's usually printed in watts (W) - e.g. a ceiling fan is around 75 W, an LED TV around 100 W, a refrigerator around 150-300 W, a 1.5-ton air conditioner around 1,500 W (1.5 kW), and a water geyser around 2,000 W (2 kW).
2. Pick the matching unit (watts or kilowatts) so you don't have to convert by hand.
3. Enter how many of that appliance you run and for how many hours a day.
4. Enter your tariff - you'll find the per-unit (per kWh) rate on your electricity bill.
5. Submit to see the daily, weekly, monthly, and yearly energy use and cost.

Example

A 1.5 kW air conditioner running 6 hours a day, with a tariff of ₹8 per kWh:

$$E_{daily} = \frac{1500 \times 6 \times 1}{1000} = 9\ kWh$$ $$Cost_{daily} = 9 \times 8 = ₹72$$

Over a 30-day month that's 270 kWh ≈ ₹2,160, and over a year about 3,285 kWh ≈ ₹26,280 - from a single appliance. Running the same AC one hour less per day would save about ₹4,380 a year.

Notes

• Appliances with compressors or thermostats (refrigerators, ACs, geysers) cycle on and off, so they don't draw their rated power continuously. For those, treat the result as an upper estimate, or enter the compressor's average running hours instead of the hours the appliance is switched on.
• Many electricity boards use slab tariffs where the per-unit rate rises with total consumption. Use the rate of the slab your household usually falls in, or your bill's effective average rate (total amount ÷ total units) for a more realistic figure.
• Standby power is not included - devices left on standby typically add a few watts each, around the clock.