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Electricity

Electricity Cost Calculator

Calculate the running cost of an appliance or load from its wattage, daily hours and electricity rate.

Annual cost = (watts ÷ 1,000) × hours/day × rate ($/kWh) × 365. A 2,000 W heater used 4 hours a day at 30 ¢/kWh costs about $876 per year.

Calculator

Annual running cost
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How it works

Convert watts to kilowatts (÷ 1,000), multiply by the daily usage hours to get kWh per day, then multiply by your tariff rate and by 365 for the yearly figure. Divide the annual result by 365 for daily cost, or by 12 for a monthly estimate.

Worked example

2,000 W ÷ 1,000 = 2 kW. 2 kW × 4 h = 8 kWh/day. 8 × $0.30 = $2.40/day. $2.40 × 365 = $876/year.

Assumptions & limitations

Uses a flat tariff rate. If you're on time-of-use pricing, use your peak or average rate. The nameplate wattage is the maximum — many appliances cycle on and off, so real consumption may be lower.

Frequently asked questions

Where do I find the wattage?

On the appliance nameplate, in the manual, or on the retailer's product page. For fridges and air conditioners the energy rating label gives kWh per year directly — you can use that instead of this calculator.

What electricity rate should I use?

Check your latest bill for the usage charge per kWh. In Australia the average is roughly 25–35 ¢/kWh depending on state and plan. If you're on time-of-use, use your peak rate for a worst-case figure or your off-peak rate for overnight loads.

How do I get the daily or monthly cost?

Divide the annual figure by 365 for daily, or by 12 for a monthly estimate. In the example above: $876 ÷ 365 = $2.40/day, ÷ 12 = $73/month.

Last updated 21 June 2026

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