Electricity cost calculator
Estimate the energy and cost of running an appliance from its wattage, daily usage and your own electricity rate.
Enter your values and press Calculate. Your inputs stay in the address, so you can switch language or share the link.
Formula
energy = power ÷ 1000 × hours per day cost = energy × days × rate
How it works
Power in watts is converted to kilowatts and multiplied by the hours used each day to get daily energy use; multiplying by the number of days and your rate gives the total cost.
Worked example
The same calculation with the default values:
- Appliance power 1,500 W
- Hours used per day 3 h
- Number of days 30
- Your electricity rate (per kWh) 0.15
- energy per day = 1,500 ÷ 1000 × 3 = 4.5 kWh
- total energy = 4.5 × 30 = 135 kWh
- cost = 135 × 0.15 = 20.25
Result: Energy per day: 4.5 kWh · Total energy: 135 kWh · Total cost: 20.25 USD
Enter your own electricity rate - no utility rate is assumed or looked up, since rates vary by provider, plan and country.
Common mistakes
- Using the appliance's maximum rated wattage instead of its typical running wattage, which overstates the cost.
- Forgetting standby ("vampire") power draw when a device is switched off but still plugged in.
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