Formula
Daily generation = system kW x 4. Self-used kWh = min(daily generation x 0.5, daily usage). Annual savings = (self-used x tariff + exported x feed-in tariff) x 365. Payback = system cost / annual savings.
Solar Panel Payback Calculator
Estimate solar payback from system size, upfront cost, electricity tariff, feed-in tariff and household usage.
Worked example
A 6.6 kW system at $8,000 with $0.28/kWh import tariff and $0.06/kWh feed-in tariff returns roughly a 6-year simple payback under the default assumptions.
Professional note
Professional note: print the input values, formula, result and date together so the calculation can be reviewed later.
Regional and unit assumptions
Basis: transparent planning arithmetic using the visible inputs and assumptions on this page.
Assumptions and limitations
- This calculator is for planning and education, not legal, tax, medical, immigration, engineering or financial advice.
- Use current official rates, contracts, carrier terms, statutes or professional guidance before relying on the result.
- The default values are examples. Replace them with the figures from the job, invoice, contract, bill, service or record being checked.
Methodology & Accuracy
How this calculator is checked
CalculationTime pages are built around visible arithmetic: the formula, assumptions, worked example and practical limitations are shown so the result can be checked rather than simply trusted.
Formula used
Daily generation = system kW x 4. Self-used kWh = min(daily generation x 0.5, daily usage). Annual savings = (self-used x tariff + exported x feed-in tariff) x 365. Payback = system cost / annual savings.
Standard or basis
Basis: transparent planning arithmetic using the visible inputs and assumptions on this page.
Where a calculator follows a named legal, trade or industry standard, that standard is cited visibly. Otherwise the page uses transparent general arithmetic and states its limits.Master's Tip
Professional note: print the input values, formula, result and date together so the calculation can be reviewed later.
Related calculators
Questions
What is the Solar Panel Payback Calculator?
The solar payback calculator estimates daily generation, self-use savings, export credits and years to recover the installed cost.
Can I rely on this as professional advice?
No. Use it as a transparent planning estimate, then verify the current rule, rate, contract or official source for the decision you are making.