Electricity Cost Calculator
Electricity is billed in kilowatt-hours (kWh), one kWh is the energy used by a 1,000-watt appliance running for one hour. Your bill is the sum of all appliance wattages multiplied by daily hours of use, divided by 1,000 to get kWh, then multiplied by your electricity rate. Australian residential rates typically range from 25–42 cents/kWh depending on your state and retailer. High-consumption appliances, electric hot water systems, pool pumps, ducted air conditioners, and EV chargers, typically account for 40–70% of household consumption. Identifying and reducing their run-time or load is the fastest route to lower bills. This calculator lets you build an appliance list with wattage and daily hours, see the cost per day, week, month, and year for each device and in total, and factor in rooftop solar generation to see your net consumption after self-consumption offsets.
Frequently Asked Questions
How is electricity usage calculated?
Electricity usage in kilowatt-hours (kWh) = Power in watts multiplied by Hours used, divided by 1,000. For example, a 1,500-watt heater running for 2 hours uses 1,500 x 2 / 1,000 = 3 kWh. Your electricity bill is calculated by multiplying total kWh used by your electricity rate in cents per kWh, plus any daily supply or standing charges that apply in your area.
What costs more to run, heating or cooling?
Heating typically costs more because heat pumps in reverse-cycle air conditioning and resistive bar heaters often use 2 to 4 times more energy than cooling in the same space. Cooling simply moves heat from inside to outside, while heating (especially electric resistance heating) generates warmth from scratch. A 2,400-watt bar heater running 4 hours costs around $2.70 at A$0.28/kWh, while a 700W portable air conditioner cooling for the same time costs under $0.80.
How much does a TV cost to run per year?
A typical 55-inch LED TV uses 80-150 watts when on and nearly zero when off (unless on standby). At A$0.28/kWh, running a 100W TV for 4 hours per day costs about $41 per year. An older plasma TV of the same size could use 300W or more, pushing annual costs over $120. Watching less, using brightness settings, and turning off completely rather than standby all reduce running costs.
What uses the most electricity in a typical home?
In most Australian homes, hot water heating accounts for the largest share (around 25-30% of electricity use), followed by space heating and cooling (20-25%), and refrigeration (10-15%). Other major users include clothes dryers, pool pumps, and lighting. Improving insulation reduces heating and cooling costs most significantly, while switching to a heat pump hot water system can cut hot water electricity by 60-70%.
What is a kilowatt-hour (kWh)?
A kilowatt-hour is the amount of energy used by a 1000-watt appliance running for one hour. It's the standard unit on your electricity bill. If you want to measure specific appliances around your home rather than relying on estimates, the Kill A Watt Connect P4498 Electricity Usage Monitor plugs into any outlet and shows real-time watts and cumulative kWh usage for any device.
How can I reduce my electricity bill?
Switch to LED bulbs, use a smart thermostat, wash clothes in cold water, dry clothes on a line instead of a dryer, and unplug phantom load devices. A Kasa smart plug with energy monitoring lets you track any appliance's real-time and historical energy draw, so you can identify the biggest culprits on your bill and set schedules to cut phantom load.