Where and when you charge sets the price
Home and overnight charging are usually cheaper than public fast charging, but a cheaper rate only helps if you can use it regularly. Our charging routine guide can help you find a workable place and time to charge, including small changes to your week.
An everyday 250 km week
The example needs 45 kWh of electricity. Of that, 32.4 kWh uses a 15 c/kWh overnight rate, 8.1 kWh uses a 35 c/kWh regular home rate and 4.5 kWh uses a 60 c/kWh public charger. That is $4.86 + $2.84 + $2.70, or about $10.40 for the week. The petrol comparison uses 21.25 litres at the ACCC’s 12 June 2026 national average price of 166.6 cents per litre. Petrol prices change weekly — adjust the petrol price in the calculator to today’s price at your local bowser.
Result: about $10 with the mixed overnight example. At a flat 35 c/kWh home rate, the same energy costs $15.75. The public-charging and petrol comparisons are in the short answer above.
Four charging situations — and what each one costs
| How you charge | This guide’s example | What to check and why |
|---|---|---|
| In the sun | 70% surplus solar, 30% regular home electricity, plus occasional public charging. | Confirm you can charge while your panels are producing. Use the export credit you give up, rather than calling solar free, or the saving will be overstated. |
| While you sleep | 80% overnight electricity, 20% regular home electricity, plus occasional public charging. | Confirm your plan, meter and charger schedule support the cheaper window. Also check peak and demand charges, because they can outweigh the EV rate elsewhere on your bill. |
| Whenever needed | The regular household usage rate, with some public charging. | Use the c/kWh usage charge on your bill so the estimate matches what you pay. The existing daily supply charge is excluded because owning the EV usually does not create it. |
| Out and about | Paid public charging. | Check the exact site in the charging app. Network, speed, membership, idle and parking fees can make one public charger cost much more than another. |
What could change the answer?
- Your vehicle's efficiency: this guide’s editable default is 18 kWh/100 km from the plug. Use metered charging or a cautious exact-car figure; the cost scales directly with it.
- Weather and speed: cold weather, high-speed driving, towing and heavy loads can increase energy use.
- Your electricity plan: a cheap EV window may come with higher peak prices or a demand charge elsewhere on the bill.
- Public-charger extras: idle fees, parking charges and subscriptions are not included in the per-kWh comparison. The public-charging etiquette guide explains when separate site fees can apply.
How to estimate your own week
- Group your driving into everyday, regular longer and occasional long trips. Calculate the ordinary week first, then add the occasional public-charging cost separately so a few road trips do not hide the savings—or costs—you repeat all year.
- Find your electricity usage rate in c/kWh on your bill and your public rate in the charging app. Using the actual rates avoids building the estimate around an offer you cannot access.
- Choose where and when you can regularly charge. Solar only helps when you can charge during solar hours; an overnight rate only helps during its cheap window.
- Enter the share you expect to charge publicly. This matters because occasional road trips cost very differently from depending on public charging every week.
- Compare energy cost first. Purchase price, finance, insurance and servicing are separate — this guide covers running costs only.
Common charging-cost questions
Is charging an EV with rooftop solar free?
Not necessarily. If the solar would otherwise be exported, using it in the car means giving up a feed-in credit. Solar equipment also has an upfront cost. For a simple marginal-cost comparison, enter the feed-in tariff you would otherwise receive.
Should I change electricity plans for an EV?
Sometimes, but compare the whole household bill. A very cheap overnight EV rate can be offset by higher peak rates, changed daily supply charges or demand charges. Use a free government comparison service where one is available in your state or territory.
Is public charging always more expensive than petrol?
No. With this guide’s default 18 kWh/100 km EV and 8.5 L/100 km petrol car at 166.6 c/L, energy costs are equal at about 79 c/kWh: (8.5 × $1.666) ÷ 18. Change either vehicle or price and the boundary changes.
Is slow public charging at hotels or shopping centres cheaper?
Sometimes. A destination charger is a slower AC charger where the car may stay parked for hours. Check the operator’s current price plus parking, idle, access or guest conditions; slower does not automatically mean cheaper.
Assumptions and sources
Default electricity rates used by the calculator:
- In the sun: 5 c/kWh as an editable surplus-solar opportunity cost and 35 c/kWh for regular electricity outside solar hours. The default home mix is 70% solar and 30% regular electricity.
- While I sleep: 15 c/kWh overnight and 35 c/kWh outside the overnight window. The default home mix is 80% overnight and 20% regular electricity. OVO Energy’s EV Plan advertised 4.5 c/kWh from midnight to 6 am when checked; eligibility, other rates and supply charges still matter.
- Whenever needed: 35 c/kWh for regular home electricity.
- Out and about: 60 c/kWh as an editable public-charging example. Check the exact site for current energy, parking, idle and membership charges.
These are editable ChooseEV examples, not Australian averages or offers. Public charging is blended into the selected home situation using the public-charging share in the calculator.
ChooseEV assumes an EV uses 18 kWh/100 km from the plug — a conservative figure for a mid-size EV; small EVs typically use 14–16 kWh, larger SUVs 20–25 kWh. The comparison petrol car defaults to 8.5 L/100 km, broadly representative of an average new Australian passenger vehicle; both figures are editable in the calculator. Costs exclude fixed supply charges, public-charger idle or parking fees and all non-energy ownership costs.
Sources:
- Australian Government: How to charge your electric vehicle — home and public charging, tariffs, solar and public-price guidance.
- Australian Government: Electricity pricing plans and tariffs — usage charges, time-of-use plans, demand charges and feed-in tariffs.
- Australian Government: Find the best energy deal — electricity bill components and official state comparison services.
- ACCC: Weekly fuel price monitoring report, 12 June 2026 — national average retail petrol price of 166.6 c/L on 12 June 2026.
Sources and examples reviewed 16 July 2026.