Solar Panel ROI Calculator
Enter your system details to estimate payback period, annual savings, and long-term return.
Solar panels reduce your electricity bills by generating free power during the day. This calculator estimates how much a system will save you each year, when it pays for itself, and the total return over 25 years — using real electricity rates, feed-in tariffs, and solar irradiance data for every Australian state.
System size
~30% without battery, ~80% with battery
Ready when you are
Enter your system details and hit Calculate ROI to see your payback period, annual savings, and 25-year return.
Frequently Asked Questions
How long do solar panels take to pay off in Australia?⌄
Most Australian households with a 6.6 kW solar system see a payback period of 4–8 years depending on their state, electricity rate, daily usage, and how much solar power they self-consume. Queensland, Western Australia, and South Australia tend to have shorter payback periods due to higher solar irradiance and electricity rates.
What size solar system do I need for my home in Australia?⌄
A 6.6 kW system is the most popular choice for Australian homes using 15–25 kWh/day. It costs roughly $6,000–$9,000 installed and generates around 25–30 kWh/day depending on your location. Larger households or those with a pool, EV, or ducted air conditioning may benefit from a 10–13.2 kW system.
What is a solar feed-in tariff in Australia?⌄
A feed-in tariff (FiT) is the rate your electricity retailer pays for excess solar energy you export back to the grid. Rates in 2025 typically range from 3–7 cents per kWh depending on your state and retailer. Because FiT rates are far lower than what you pay to buy electricity, self-consuming solar power is more valuable.
Which Australian state gets the best return on solar panels?⌄
Queensland and Western Australia have the highest solar irradiance, meaning panels generate more electricity per kW installed. South Australia has high electricity rates, making savings per kWh larger. Victoria and Tasmania have lower sun hours but reasonably competitive electricity rates.
Do I need a battery with my solar panels?⌄
A battery increases self-consumption from ~30% to ~80%, significantly improving returns since self-consumed solar replaces expensive grid electricity rather than being exported at low feed-in tariff rates. However, home batteries cost $8,000–$15,000 and have their own payback period, so they are best evaluated as a separate investment.