Kilowatt-hours and cost from watts, hours per day, tariff, and days.
| kWh | – |
| Cost | – |
Use this calculator for an appliance on the bill: a heater, a dryer, or a PC that stays on.
kWh = (watts / 1000) × hours per day × days. Cost is kWh × price per kWh. A 1000 W heater for 2 hours a day at 0.25 per kWh over 30 days is 60 kWh and 15.00. Standby watts still count. Match the tariff to what the bill uses (energy only, or energy plus fees).
Watts: Power draw of the appliance.
Hours per day: Hours it runs each day.
Price per kWh: What you pay per kilowatt-hour.
Days: How many days to total.
kWh: Energy used.
Cost: Money for that energy.
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