How to use the Appliance Electricity Cost Calculator
- Enter the appliance’s power in watts, from its label or manual.
- Enter how many such appliances you run and the hours per day.
- Enter the price per unit (kWh) from your electricity bill.
- Read the cost per day, month and year, and the units used.
Formula used
Units (kWh) = watts × number of appliances × hours ÷ 1,000. Cost = units × price per unit. Month = 30 days, year = 365 days.
Worked example
Here is the Appliance Electricity Cost Calculator worked through with the example values shown above, so you can check each step by hand.
| Inputs | |
|---|---|
| Power of one appliance | 1,500 watts |
| Number of appliances | 1 |
| Hours used per day | 8 hours |
| Price per unit (kWh) | ₹8 |
| Result | |
| Cost per month (30 days) | ₹2,880.00 |
| Cost per day | ₹96.00 |
| Cost per year | ₹35,040.00 |
| Units (kWh) per day | 12 |
| Units (kWh) per month | 360 |
Monthly cost by hours of use
For a 1,500 watt appliance at ₹8 per unit.
| Hours used per day | Units (kWh) per month | Cost per month (30 days) |
|---|---|---|
| 2 hours | 90 | ₹720.00 |
| 4 hours | 180 | ₹1,440.00 |
| 6 hours | 270 | ₹2,160.00 |
| 8 hours | 360 | ₹2,880.00 |
| 12 hours | 540 | ₹4,320.00 |
| 24 hours | 1,080 | ₹8,640.00 |
How the cost is worked out
One unit of electricity is a kilowatt-hour (kWh), the energy used by 1,000 watts running for an hour. The calculator multiplies watts by the number of appliances and the hours, and divides by 1,000. A 1,500 watt appliance run for 8 hours uses 12 units a day, or 360 units in a 30-day month.
At ₹8 a unit that is ₹96 a day, ₹2,880 a month and ₹35,040 a year. At ₹10 a unit the monthly cost becomes ₹3,600.
Some everyday comparisons
A ceiling fan of 75 watts used 10 hours a day uses 22.5 units a month and costs ₹180 at ₹8. Ten LED bulbs of 9 watts for 6 hours a day use 16.2 units and cost ₹130.
A 2,000 watt water heater run for one hour a day uses 60 units a month and costs ₹480. High-power appliances that run for long hours, such as air conditioners and heaters, tend to dominate a bill.
Appliances that cycle
Refrigerators, air conditioners and some heaters switch their compressor or element on and off to hold a temperature. Their label shows the power while running, but they are not on all the time. Enter the hours it is actually running, or use a lower average figure. An inverter AC also draws less than its maximum most of the time.
The most accurate way is a plug-in energy meter, which shows the real units used over a week or month.
Finding your tariff
The price per unit is on your bill, and in many places it rises in steps as consumption increases. Use the rate that applies to your highest slab for a fair marginal cost, or divide your bill by the units used for an average. Fixed charges and taxes add to the real cost, so your total may be higher.
To bring bills down, look at the biggest line first: efficient appliances, sensible thermostat settings and turning things off make the largest difference.
Frequently asked questions
What is a unit of electricity?
One kilowatt-hour (kWh): 1,000 watts used for one hour.
How do I find an appliance’s watts?
Look at the rating label. If it shows volts and amps, multiply them.
Why is my bill higher than the sum of appliances?
Fixed charges, taxes, standby power and slab rates add to it.
Does an AC use full power all day?
No. The compressor cycles on and off. Enter the hours it runs, or a smaller average.
How many days does a month have here?
The monthly figure uses 30 days and the yearly one 365.
Can I use another currency?
The tariff box uses ₹, but the arithmetic works for any currency price per unit.
This calculator gives estimates for information only. Actual figures from a bank, employer, tax authority or doctor may differ. It is not financial, tax, legal or medical advice.