AU Solar & Battery Payback Calculator

Estimate how long rooftop solar might take to pay for itself in Australia. Enter your own figures — no prices are pre-filled from any retailer.

System size (kW) System cost ($, after any rebate you actually received) Household electricity use (kWh per day) Share of solar you use yourself (%) Electricity price you pay (cents per kWh) Feed-in tariff you receive (cents per kWh) Average generation per kW per day (kWh) — default 4.2, change it if your installer gave you a local figure

Assumptions, shown openly

Annual generation = system kW × generation per kW per day × 365.
Self-used solar cannot exceed your annual household use.
Yearly saving = self-used kWh × price you pay + exported kWh × feed-in tariff.
Payback = system cost ÷ yearly saving. The 10-year figure is yearly saving × 10 − system cost. It does not include panel degradation, inverter replacement, maintenance, or price changes.

Estimates only, not financial advice. See the Disclaimer.