Energy Cost Calculator
Estimate electricity use and cost for one appliance or combine up to three daily appliance schedules.
Monthly energy cost
Uses average power at the wall and a constant unit price. Standing charges, time-of-use tariffs, tiered prices and seasonal schedules are excluded. Currency display is configurable and does not convert amounts.
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How this calculator works
Multiply each appliance’s representative average watts by its daily operating hours, then divide the sum by 1,000 to obtain kWh. Apply the energy-unit price to estimate incremental cost. Separate appliances can run at the same time, so their hours need not sum to 24. For equipment that cycles, measured average demand is more representative than the maximum label rating. Annual cost uses 365 copies of the entered daily schedule.
Formula
Daily kWh = Σ(appliance average W × daily hours) / 1,000. Daily cost = kWh × unit price. Monthly cost = daily cost × selected days. Annual cost = daily cost × 365.
Assumptions & limitations
Uses average power at the wall and a constant unit price. Standing charges, time-of-use tariffs, tiered prices and seasonal schedules are excluded. Currency display is configurable and does not convert amounts.
Worked example
A 1,000 W appliance for 2 hours and a 100 W light for 5 hours consume 2.5 kWh daily. At 0.20 per kWh, cost is 0.50 daily, 15.00 for a 30-day month and 182.50 for 365 days in the selected currency.
Our approach to calculations ↗Common questions
Should I use rated watts or measured average watts?
Use representative wall-power measurements when possible. Cycling appliances often consume less than their maximum labelled watts over a full hour.
Why does annual cost differ from monthly cost times twelve?
Annual cost uses 365 days; twelve copies of a 30-day month contain only 360 days.
How does this differ from PC electricity calculators?
This tool combines general appliances. PC Electricity Cost models one computer average, and Gaming PC Electricity Cost separates gaming and idle states.