Electricity Cost Calculator
Work out what any appliance costs to run per day, month and year, estimate your monthly electricity bill from kWh, or see if a new appliance pays for itself. Works with any currency.
For information only. Real costs depend on your tariff, taxes and how the appliance is used. Check your bill for your price per kWh.
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How to calculate electricity cost
Every appliance label shows its power in watts. Electricity is sold by the kilowatt-hour (kWh), the energy used by 1,000 watts running for one hour.
- Energy (kWh) per day = watts × hours used per day ÷ 1,000.
- Cost per day = kWh per day × your price per kWh.
- Cost per month = cost per day × days used. Cost per year = cost per month × 12.
Example: a 1,500 W air conditioner running 8 hours a day uses 12 kWh a day. At 0.17 per kWh that is 2.04 a day, 61.20 a month and 734.40 a year.
Watts to kWh: divide the watts by 1,000, then multiply by the hours. 100 W for 10 hours is 1 kWh.
Cost of charging an electric car: use the electric car charger option, or multiply the kWh added to the battery by your price per kWh. Adding 40 kWh at 0.17 costs 6.80.
Units and kWh: in Pakistan, India and some other countries, bills show “units”. One unit is the same as one kWh, so you can enter your units in the kWh box. In the US and UK bills show kWh.
Find your price per kWh on your electricity bill. Some bills show tiers or peak and off-peak prices: use the one that matches when you run the appliance.
Typical appliance running costs
These use the typical watts and hours the calculator fills in, a 30-day month and a price of $0.17 per kWh. Your own cost will differ.
| Appliance | Power | Hours per day | Energy per month | Cost per month |
|---|---|---|---|---|
| Air conditioner | 1,500 W | 8 h | 360 kWh | $61.20 |
| Refrigerator | 150 W | 8 h | 36 kWh | $6.12 |
| Water heater | 3,000 W | 3 h | 270 kWh | $45.90 |
| Electric car charger | 7,000 W | 4 h | 840 kWh | $142.80 |
| Television | 100 W | 5 h | 15 kWh | $2.55 |
| Washing machine | 500 W | 1 h | 15 kWh | $2.55 |
| Laptop | 50 W | 6 h | 9 kWh | $1.53 |
| LED bulb | 10 W | 5 h | 1.5 kWh | $0.26 |
How to cut your electricity bill
- Run the biggest loads least: air conditioners, water heaters and space heaters cost the most.
- Use the replace option to see if an efficient appliance pays for itself.
- Switch off standby devices and use LED bulbs.
- Run heavy appliances in off-peak hours if your tariff has them.
Frequently asked questions
How do I calculate electricity cost?
Multiply the appliance watts by the hours used and divide by 1,000 to get kWh. Multiply the kWh by your price per kWh. For 1,500 W for 8 hours at 0.17 per kWh, that is 12 kWh and a cost of 2.04 per day.
How do I convert watts to kWh?
Divide the watts by 1,000 and multiply by the hours of use. A 100 W bulb on for 10 hours uses 1 kWh.
How much does it cost to run an air conditioner?
A 1,500 W unit running 8 hours a day uses about 360 kWh a month. At 0.17 per kWh that is about 61 a month. Larger units and longer hours cost more.
How do I calculate the cost of charging an electric car?
Multiply the kWh added to the battery by your price per kWh. Adding 40 kWh at 0.17 costs 6.80. Charging losses add a little more, usually around 10%.
How do I calculate my monthly electricity bill?
Choose Monthly bill. Enter the kWh from your meter or bill, your price per kWh, any fixed charge and tax. The calculator adds them up.
Where do I find my price per kWh?
It is on your electricity bill or tariff. If your bill shows a total and the kWh used, divide the total by the kWh for an average price.
How do I know if a new appliance is worth buying?
Choose Replace an old appliance, enter the old and new watts, the hours per day, the new price and your electricity price. It shows the yearly saving and how many years until the saving covers the price.
What is a unit of electricity, and how do I convert kWh to units?
One unit of electricity is one kilowatt-hour (kWh). Bills in Pakistan, India and other countries say “units”, and a bill that shows 300 units means 300 kWh. So kWh to units is a 1 to 1 conversion: no calculation is needed.
How do I calculate my electricity bill from units?
Multiply the units (kWh) by the price per unit. Add any fixed charge and tax. Some countries charge a higher price per unit as usage goes up (slab or tier rates), so check which price applies on your bill.
Are the typical watts accurate?
They are typical values. Real power varies by model, load and settings. Check the label or manual for your appliance, then type the watts in.
About this calculator
Free electricity cost calculator for appliances, monthly bills and replacement savings. It works in any currency, runs in your browser and does not store your numbers. Last updated November 11, 2026. Questions or corrections: [email protected].
Written by Umar Khan
Umar Khan is a PhD student in engineering at NTNU, the Norwegian University of Science and Technology, in Norway. Every formula and worked example on this page is shown in full so you can check each result yourself. Corrections are welcome at [email protected].
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For information only, not professional advice.
Written by Umar Khan. Last updated: November 11, 2026.