Electricity Cost Calculator
The Electricity Cost Calculator estimates an appliance’s energy consumption in kilowatt-hours and its cost using wattage, daily usage, billing days, and a price per kWh. An optional daily standing charge can be included.
How to use this calculator
- Enter the appliance power rating in watts.
- Enter hours of operation per day and the number of days.
- Enter the energy tariff per kilowatt-hour.
- Optionally enter a daily standing charge to add a share of fixed costs.
Energy use and electricity cost
Energy (kWh) = watts ÷ 1,000 × hours per day × days; variable cost = energy × price per kWh; total = variable cost + daily charge × days.
- Watts are converted into kilowatts before multiplying by the time used.
- The standing charge is calculated separately from energy consumption.
- The result is an estimate, because real tariffs can use time bands, tiers, taxes, and other charges.
Worked examples
Appliance running cost
A 100 W device runs for 5 hours each day over 30 days at €0.30 per kWh.
0.1 kW × 5 × 30 = 15 kWh; 15 × €0.30 = €4.50.
The energy cost is €4.50 before standing charges or other bill items.
Understanding the result
Higher wattage and longer operation increase energy consumption.
The cost estimate depends on the tariff and does not forecast changes in future energy prices.
Important notes
Use the tariff shown on your bill and the same currency throughout.
Appliance power draw may vary during operation, so rated watts can be an approximation.
Frequently asked questions
How many kWh does an appliance use?
Multiply power in kilowatts by the number of hours used.
Does this include standing charges?
Yes, when you enter a daily standing charge; other taxes and tariff-specific charges may still be excluded.
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Related explanations
Learn the method behind the number or compare the terminology before using the calculator.
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This page provides a calculation tool plus explanatory information so you can understand what the result means and when the underlying method may not fit your situation.