Calculator
What could solar and a battery save you?
Four quick questions, no sign-up. See the installed price after rebates and what it could save you each year.
Where's your home?
Your postcode sets your sunshine, your rebates and your electricity prices.
How the calculator works
- Your usage comes from your bill. Without solar, we remove the fixed supply charge and divide by the usage rate. With solar, your bill includes solar credits, so we rebuild your total use from grid usage plus the solar you use yourself; enter the kWh from your bill for a closer figure.
- Your rates default to a reference electricity plan for your state, including a typical feed-in tariff for that state. Enter the rates on your bill to replace them.
- One energy balance for the year: solar is used in the home first (25 to 40% of generation, up to 70 to 90% of your daytime use), a battery charges only from the solar left over, and the rest is exported. Solar is sized to produce about 110% of your yearly use, using the Clean Energy Regulator's zone rating for your postcode.
- Batteries are sized to cover about 90% of your evening use. We count 250 to 320 equivalent full cycles a year (not days in use), about 10% lost charging and discharging, and never more than your spare solar or evening use. On a premium feed-in tariff we show the effect while it lasts and after it ends.
- Prices are typical Australian market ranges before rebates, less the federal solar and battery discounts for your postcode and today's date. STC discounts are calculated at $37 per certificate; your installer confirms the final credit. State incentives are checked separately and not deducted unless they're a fixed amount. Get your price for your address from a vetted installer.
- Replacing a system is compared with keeping it (or, if it has stopped, with leaving it off). A complete replacement can claim the solar rebate again; removing the old system is included.
- First-year savings and payback: savings are the first year's, at today's prices. Payback is when they add up to the price after discounts, with electricity prices rising 3% a year after the first year (a little below the last 10 years' average of 3.3%, ABS) and, for solar, panels ageing 0.5% a year. No battery wear or finance costs. A 10-year modelling period is used for comparison; it isn't a battery's lifespan.
- The VPP scenario is never in the headline. It adds recurring credits and event payments, less fees and the savings you give up on the share of battery cycles the operator uses; a one-off joining credit, if you enter one, comes off the price. The example starts at $200 a year in credits and 10% battery use, with no joining credit counted: change them to your plan's figures. An example, not a specific plan: published VPP offers pay about $80 to $450 a year in credits (checked 1 Oct 2026), mostly capped, so they don't grow much with battery size. Some add a one-off joining credit, often $200, which isn't counted here. Wholesale-price plans vary more and can cost more in some years.
Rebate rules verified 26 September 2026. Savings model 2026-10-02.
Learn more: what size battery you need, how the battery rebate works and adding a battery to existing solar. General information, not financial advice.
Questions people ask
How accurate is the solar and battery savings calculator?
It's an estimate for comparing options, built on your bill, your state's reference plan (or your own rates) and your postcode's solar zone. Your real savings depend on when you use power, your roof and your plan; your installer's design and your own bills give the closer figure.
Does the calculator include the rebates?
Yes, the federal solar and battery rebates for your postcode and today's date, at about $37 per certificate. State incentives are listed separately and only taken off when they're a fixed amount for everyone.
Why is the battery payback longer than solar's?
A battery saves money only on the solar it stores and uses in the evening instead of exporting it, so it earns the difference between your usage rate and your feed-in tariff on each stored kWh. Solar saves the full usage rate on every kWh you use as it's made.
Is a virtual power plant included in the savings?
No, never in the headline. The VPP scenario is shown separately, with the credits less what you give up on the battery cycles the operator uses, so you can enter your own plan's figures.
Can I use my own electricity rates?
Yes. Enter the usage rate and feed-in tariff from your bill to replace the reference plan for your state.