Solar Panel Payback Calculator
Find out how long your solar panels take to pay back their installation cost — and what the lifetime return looks like. Enter your annual production, electricity price and installation cost to get payback period, ROI and 25-year net savings.
Don't know your annual production yet? Use the Solar Panel Calculator to estimate it first →
Quick Start
Tip: Get your annual production estimate from a solar installer or from the Solar Panel Calculator. This calculator handles the financial side only.
Project
System & Installation
Pricing & Settings
Export tariff is kept flat (not inflation-adjusted) — a conservative assumption, since feed-in rates are typically set by policy rather than rising with energy prices.
Common solar payback questions
How long do solar panels take to pay back?+
Typically 6–12 years, depending on location, electricity prices, grants and self-consumption rate. In high-sunshine areas with strong grants and high electricity prices, payback can be 4–6 years. Most panels are guaranteed for 25 years, so even a 10-year payback leaves 15 years of net profit.
What is self-consumption rate and why does it matter?+
Self-consumption is the share of solar production you use directly rather than exporting. Self-consumed electricity saves at full retail price; exported electricity earns only the feed-in tariff, which is typically lower. Higher self-consumption = shorter payback. Typical rates: 30–50% without battery, 60–80% with battery.
Why is the export tariff kept flat in this calculator?+
Export tariffs are typically set by government policy or contract for a fixed period rather than rising with energy markets. This calculator inflates your electricity price each year (since retail prices historically rise) but keeps the export tariff flat as a conservative assumption. You can adjust both figures to match your specific contract.
What is panel degradation and how much does it matter?+
Panels lose a small percentage of output efficiency each year — typically 0.3–0.8%. Most manufacturers guarantee at least 80% of rated power after 25 years. This calculator accounts for it year by year. At 0.5% per year, year 25 production is about 88% of year 1 — a meaningful but not dramatic reduction.
How solar payback is calculated
What this calculator does — and does not do
This calculator handles the financial payback analysis for a solar installation. It does not estimate how many panels you need or what your annual production will be — use the Solar Panel Calculator for that, then bring your annual kWh figure here.
Year-by-year model
For each year from 1 to the system lifetime, the calculator computes:
- Production adjusted for degradation:
prod × (1 − degradationRate)^(year−1) - Self-consumption savings:
prod × selfConsumption% × electricityPrice × (1 + inflation)^(year−1) - Export income (flat tariff):
prod × (1 − selfConsumption%) × exportTariff - Net year saving:
selfConsumptionSaving + exportIncome − maintenance
Payback is the first year where cumulative net savings equal or exceed the net installation cost. If this never happens within the selected lifetime, the calculator shows "No payback within selected lifetime."
Why export tariff is flat
Electricity retail prices tend to rise with inflation — your savings on self-consumed electricity grow accordingly. Export tariffs, however, are typically set by government scheme or contract and do not automatically rise. Keeping the export tariff flat is the more conservative and realistic assumption for most homeowners.
Wondering how many panels you need? Read How Many Solar Panels Do I Need?