Watts to cost
Electricity Cost Calculator
Turn appliance watts and usage hours into kWh and a clear electricity-cost estimate.
Live calculator
Calculate your actual running cost
Estimated monthly cost£79.20303.3 kWh per month
Per hour£0.52
Per day£2.61
Per year£950.40
Running this electric heater for 5 hours a day, 7 days a week uses about 303.3 kWh each month.
The formula
How electricity cost is calculated
Divide watts by 1,000 to convert power to kilowatts. Multiply kilowatts by the hours used to get kWh, then multiply kWh by your unit price. A 1,000 W appliance used for two hours consumes 2 kWh. At 26.11p per kWh, that example is about £0.52. Use your own unit rate.
Use your actual unit rate
Your electricity bill normally lists a unit rate per kWh. Fixed service or standing charges should not be added to an individual appliance calculation because you pay them regardless of whether that appliance is running.