Free tool

Solar cost and payback calculator

Enter a system size and price (from a quote, or our typical range of $2.30–3.40 per watt) to see savings and payback using your utility’s actual rate structure and export rules.

How this calculator works

It works out your electricity bills with and without solar for each of 25 years, using your utility’s fixed charges, energy tiers, delivery charges, export rules and GST, with prices rising by the rate you choose. Payback is when cumulative savings, after maintenance and an inverter replacement, exceed what you paid. Read the full methodology.

It can’t see your roof. Orientation, shading and roof angle can change production a lot, which is what our $4.99 report measures.