Electricity Cost Calculator
Enter the appliance wattage, how many hours a day it runs and your electricity price to see its running cost.
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Formula
energy per day (kWh) = watts × hours per day ÷ 1000cost per day = energy per day × price per kWh- Month = 365 ÷ 12 days, year = 365 days.
Worked example
A 2000 W appliance used 2.5 hours a day at 0.20 per kWh:
- Energy per day: 2000 × 2.5 ÷ 1000 = 5 kWh
- Cost per day: 5 × 0.20 = 1.00
- Per month: 5 × 30.4167 = 152.08 kWh, costing 30.42
- Per year: 5 × 365 = 1825 kWh, costing 365.00
Assumes constant power draw at the rated wattage and a flat price per kWh.
Frequently asked questions
How do I calculate what an appliance costs to run?
Multiply watts by hours used and divide by 1000 to get kWh, then multiply by your price per kWh. A 1500 W heater for 3 hours uses 4.5 kWh; at 0.15 per kWh that is 0.68 a day.
How many days are in a month for this calculation?
A month is taken as 365 ÷ 12 = 30.42 days and a year as 365 days. So 4.5 kWh a day becomes 136.88 kWh a month and 1642.5 kWh a year.
Where do I find my appliance wattage?
Look at the rating label or manual. If it only gives volts and amps, multiply them: 230 V × 5 A is about 1150 W. Appliances with thermostats, such as fridges, run at full power only part of the time, so use the average draw.
Does this include standing charges or taxes?
No. It uses only the single price per kWh you enter. Add taxes into that price if your bill shows them per unit. This calculator is for learning and design checks only. It is not a safety certification: wiring, breaker and cable sizing must follow your local electrical code and be checked by a qualified electrician.