Solar ROI / Payback Calculator

Estimate solar energy production, yearly savings, payback period, LCOE, NPV, IRR and 25-year cash flows. Adjust assumptions to match your home.

System & Costs

System size (kW)

Typical home: 4–10 kW

Installed cost ($/W)

Or set total cost directly below

Total installed cost ($)

Overrides $/W if filled

Incentive / rebate (%)

e.g., 30% tax credit

O&M per year (% of initial cost)

Cleaning/inspection/insurance

Degradation (%/yr)

Typical 0.3–0.8%/yr

Production & Rates

Peak sun hours (hours/day)

Location-specific average

Performance ratio

Losses (inverter, temp, wiring)

Home usage (kWh/day)

Average daily consumption

Utility rate ($/kWh)

Your latest bill rate

Utility escalation (%/yr)

Expected annual increase

Net metering credit (0–100%)

Credit for excess exports

Finance & Metrics

Analysis years

Discount rate (%/yr)

For NPV/IRR

Loan APR (%/yr) [optional]

Leave empty for cash purchase

Loan term (years)

Compare Solar vs Grid →

Results

Simple payback

—

LCOE (Levelized Cost of Energy)

—

All-in cost per kWh over analysis period

NPV @ 5%

—

Present value of savings minus costs

IRR

—

Annualized return on investment

25-Year Cash Flow

Year	Prod (kWh)	Rate ($/kWh)	Savings ($)	O&M ($)	Loan ($)	Net Cash Flow ($)	Cumulative ($)
Totals	—		—	—	—	—

Notes: Savings limited to your usage if net-metering credit < 100%. Production degrades annually. Loan modeled as level monthly payment, shown as yearly total.