Electrical Energy Cost Calculator
Estimate electrical energy use and running cost from power and operating time, or from a known energy quantity, with worked steps and a printable report. Runs locally in your browser.
Electrical Energy Cost Calculator
Estimate electrical energy use and running cost from power and operating time, or from a known energy quantity.
Calculation setup
Results
Enter the required values to see a result.
Worked calculation
Enter valid values to see the worked calculation.
Formula
Energy per use (kWh) = Power (kW) × Time (h) (selected)
Active-day energy = Energy per use × Uses per active day
Average daily energy = Active-day energy × Days used per week ÷ 7
Weekly energy = Average daily energy × 7
Average monthly energy = Average daily energy × (365 ÷ 12)
Yearly energy = Average daily energy × 365
Cost = Energy (kWh) × Tariff (major currency units per kWh)
Average month is calculated as 365 ÷ 12 days (approximately 30.4166666666667 days) - never 30 days or 4 weeks.
Local processing
All calculations run locally in your browser. This tool does not upload or store the values you enter.
Assumptions and limitations
Estimate only — not a supplier bill. The electricity tariff is entered manually and is not looked up from a live supplier feed. Standing charges are excluded, and VAT or other taxes are not added separately. Tiered tariffs, time-of-use tariffs, export payments and negative tariffs are excluded. Appliance duty cycles and standby use are not automatically modelled - the entered power and time already represent actual use. Actual bills may differ from this estimate due to meter readings, tariff structure, billing periods and supplier adjustments.
Related tools
Electrical Energy Cost Calculator
Electrical Energy Cost Report
Generated 20 July 2026 at 02:57
Conversion summary
Formulas
Energy per use (kWh) = Power (kW) x Time (h). Average daily energy = Active-day energy x Days used per week / 7. Weekly energy = Average daily energy x 7. Average monthly energy = Average daily energy x (365 / 12). Yearly energy = Average daily energy x 365. Cost = Energy (kWh) x Tariff (major currency units per kWh).
Worked calculation
- Enter the required values to see the worked calculation.
Assumptions and limitations
Estimate only — not a supplier bill. The electricity tariff is entered manually and is not looked up from a live supplier feed. Standing charges are excluded, and VAT or other taxes are not added separately. Tiered tariffs, time-of-use tariffs, export payments and negative tariffs are excluded. Appliance duty cycles and standby use are not automatically modelled - the entered power and time already represent actual use. Actual bills may differ from this estimate due to meter readings, tariff structure, billing periods and supplier adjustments.
Local processing
All calculations run locally in your browser. This tool does not upload or store the values you enter.
Informational use and independent verification
Estimate only — not a supplier bill. Average month is calculated as 365 ÷ 12 days (approximately 30.4166666666667 days) - never 30 days or 4 weeks.