What is the Energy Calculator?
The energy calculator is a free online tool that helps you work out energy quickly and accurately. It uses the standard formula kWh = power(kW) x hours x days; cost = kWh x tariff and shows the result instantly as you type, along with a full breakdown so you can see exactly how the answer was reached.
How to use this calculator
- Enter appliance wattage.
- Enter daily usage hours.
- Enter the tariff and days.
- See energy and cost.
Formula used
kWh = power(kW) x hours x days; cost = kWh x tariffExplanation of each input
- Appliance power (W) โ the appliance power used in the calculation.
- Hours per day (h) โ the hours per day used in the calculation.
- Electricity tariff (INR/kWh) โ the electricity tariff used in the calculation.
- Days โ the days used in the calculation.
Understanding your result
- Energy used โ the calculated energy used in kWh.
- Cost โ the calculated cost.
Step-by-step calculation
For the example values 1000W, 5h, 8/kWh, 30d:
- Apply the formula:
kWh = power(kW) x hours x days; cost = kWh x tariff - Substitute the values: 1 x 5 x 30 x 8
- Result: 150 kWh, 1200
Worked example
| Inputs | 1000W, 5h, 8/kWh, 30d |
|---|---|
| Working | 1 x 5 x 30 x 8 |
| Result | 150 kWh, 1200 |
Benefits and practical uses
This calculator saves you time and reduces errors when you need energy. It is useful for students, professionals and anyone who wants a fast, reliable answer without manual calculation. Results update instantly, work in your browser and can be copied or shared in one click.
Assumptions and limitations
- Constant power draw; flat tariff.
Frequently asked questions
What is a kWh?
A kilowatt-hour - using 1000 watts for one hour. Your bill is based on kWh.
Disclaimer: Results are provided for general information. Please verify important figures independently.