Electricity Cost Calculator
See which appliances contribute to your electricity bill. Add measured average or rated watts, daily runtime, cycling and standby power. The comparison separates usage cost from a fixed daily supply charge.
Your result
How the calculation works
Daily kWh = quantity × (active watts × on-hours × duty fraction + standby watts × off-hours) / 1,000. Usage cost = kWh × entered tariff. Annual estimates use 365 days.
Worked example
A 200 W computer used for 8 hours at 100% duty, with 2 W standby for the other 16 hours, consumes 1.632 kWh/day. At $0.25/kWh it costs $0.408/day or $148.92/year, before fixed charges.
Assumptions and limitations
Rated watts can exceed average consumption. If a meter supplies average watts, use 100% duty to avoid reducing the figure twice. Standby is applied only outside entered on-hours. No location-specific tariffs are supplied.
Use an energy meter for variable loads such as refrigeration. This is a flat-rate model: time-of-use rates, demand charges, taxes and seasonal runtime require separate scenarios.
Sources and editorial responsibility
Maintained by Renvoro Pty Ltd. Sources inform the methods and assumptions shown here; outputs have the limitations described on this page.
Method reviewed 2026-10-11. Calculation standards · Report an issue