Check the contract before signing

Solar loan calculator

Compare the price paid in cash with the full cost of a fixed-rate solar loan. Separate the financed price, interest and optional extra principal so a low monthly payment does not hide the total.

Compare cash and a fixed-rate loan

Prefilled numbers are an editable example, not a current loan offer.

Financed price methodFinanced price before down payment ($)

Cash price for the same scope ($)Down payment ($)Contract interest rate (%) — used for paymentsDisclosed APR (%) — optional referenceTerm (years)Optional extra principal payment ($)Extra payment after scheduled month

Model a recast after the extra payment only if the contract permits it; otherwise keep the payment and shorten payoff.

APR is retained as a reference and is not substituted for the contract interest rate. No tax-credit payment is assumed. Recast fees, deferred interest, variable rates, lender-specific rounding and payment jumps are outside this model.

Total cost, not just the monthly payment

Calculate to see principal, payments, interest and the difference from paying cash.

How the calculation works

For a monthly rate r and n payments, payment = principal × r / (1 − (1 + r)⁻ⁿ). At 0% interest, payment = principal / n. Extra principal is applied after the selected scheduled payment. Recasting recalculates the payment over the remaining original term; without recasting, the payment stays the same until payoff. The model assumes monthly payments and no fees beyond the entered price.

For the same scope, $24,000 cash versus $30,000 financed is a $6,000 difference: 25% of the cash price and 20% of the financed price. Those percentages describe the same difference using different denominators.

CFPB's 2024 research describes risks from solar financing markups and conditional payment changes. It does not establish the fee in your proposal. Read the CFPB report.

SolarCalcNow provides planning estimates only. Results are not installer quotes, engineering designs, tax advice, financing recommendations, or utility interconnection approval.

Check the system price Compare ownership with lease or PPA Financing contract checklist