Electricity use & cost
Electricity use & cost: use appliance power, hours used per day, number of days. Review the formula, worked example and calculation steps.
Inputs
Use the units shown—
Enter your values and select Calculate.
Formula & explanation
Cost = power W/1000 × hours/day × days × price/kWh
Variables & units
- Appliance power
- W · minimum 0, maximum 1000000000000
- Hours used per day
- h/day · minimum 0, maximum 24
- Number of days
- Numeric value · minimum 0, maximum 3660
- Energy price
- currency/kWh · minimum 0, maximum 1000000000000
Worked example
1,000 W for 3 hours daily over 30 days uses 90 kWh; at 8 per kWh it costs 720.
Assumptions
Constant power and tariff; excludes standby changes, demand charges, taxes and tariff tiers.
Formula version 1.0.0. JavaScript floating-point arithmetic applies. Results display up to 6 decimal places; stored values retain available precision. Use the units shown.
Practice with an example
Use the default input values to find the answer. The reset icon restores those values.
Calculated on your device. Your latest 100 calculations stay in this browser.