How the Electricity Cost Calculator Works (With a Worked Example)
Works out how much an appliance costs to run. This guide walks through what each input means, the formula behind the answer and a worked example using typical Australian figures. You can follow along in the free Electricity Cost Calculator.
Why it matters
Some of the most useful calculations are the small everyday ones: how much a road trip costs in fuel, what an appliance adds to the power bill, or how many working days are left until a deadline.
What you need to enter
The calculator asks for 3 inputs. The table shows each one with the example value used later in this guide.
| Input | Example value |
|---|---|
| Appliance power (watts) | 2000 |
| Hours used per day | 3 |
| Tariff (cents per kWh) | 32 |
The formula
kWh = watts ÷ 1000 × hours. Cost = kWh × tariff.
Worked example
Entering the example values above gives these results:
| Result | Value |
|---|---|
| Cost per quarter (91 days) | $174.72 |
| Energy per day | 6 kWh |
| Cost per day | $1.92 |
| Cost per year | $700.80 |
The headline figure is $174.72 (cost per quarter (91 days)). Change any input in the calculator and every result updates instantly, so you can test different scenarios side by side.
How the cost per quarter (91 days) changes with appliance power
The table below keeps every other input at the example value and moves only “Appliance power (watts)” up and down by 10% and 20%. It shows how sensitive the cost per quarter (91 days) is to that one figure.
| Appliance power (watts) | Cost per quarter (91 days) |
|---|---|
| 1,600 | $139.78 |
| 1,800 | $157.25 |
| 2,000 | $174.72 |
| 2,200 | $192.19 |
| 2,400 | $209.66 |
At 1,600 the result is $139.78; at 2,400 it is $209.66. If a small change in this input moves the answer a lot, it is worth double-checking that figure before you rely on the result.
A practical tip
Check your bill for time-of-use tariffs. Running appliances off-peak can be much cheaper.
Keep going
Before relying on the number, read Getting the Most From a Electricity Cost Calculator: Tips and Common Errors. You might also find these guides useful:
- Solar Payback Calculator: Formula, Example and What the Result Means
- Using a Age Calculator in Australia: A Step-by-Step Guide
- Days Between Dates Calculator Explained for Australians
Frequently asked questions
- Are the results exact?
- Maths calculations are exact. Cost calculations depend on the prices and usage you enter.
- Do the date calculators handle leap years?
- Yes. They use real calendar dates.
- Can I suggest a calculator?
- Yes. Use the contact page to request one.
Run your own numbers in the Electricity Cost Calculator.
Open the calculatorGeneral information only. Rates and thresholds change, usually on 1 July. Confirm current figures with the ATO or the relevant authority, and get personal advice for decisions about your situation.