Solar Loan Calculator

For a reducing-balance quote the calculator uses the standard amortisation formula: your loan amount (system cost minus down payment) times your monthly interest rate, divided by one minus your monthly rate raised to the negative number of payments. For a flat-rate quote it charges interest on the original amount for every year of the term, adds it to the principal, and divides by the number of months. Both are the conventions lenders themselves use.

Yes. It is currency-neutral and country-neutral: type your country into the first field — 139 are covered — and the payment, total interest, and net monthly cost come back in that country's currency, formatted with its own local conventions. Loan amortisation is arithmetic, not a national standard, so the same formula applies whether you are financing a rooftop system in Germany, Nigeria, India, Australia, or Brazil.

Yes — that is what the first field is for. Start typing a country and the list narrows to it: "Kenya" finds the shilling, "Senegal" finds the West African CFA franc, "Holland" finds the euro. Common alternate spellings work too, including UK, USA, UAE, Ivory Coast, Burma, and Turkey. You can equally search by currency name, ISO code, or symbol if you already know it.

A reducing-balance rate charges interest only on what you still owe, so the interest portion shrinks with every payment. A flat (or add-on) rate charges interest on the full original amount for the whole term, regardless of how much you have repaid. A flat rate therefore costs far more than the same number quoted as an APR — a 6.5% flat rate over 15 years works out to roughly 10.4% APR. Select the basis your lender used and the calculator will show the equivalent APR so you can compare offers on the same footing.

It covers 95 currencies used across 139 countries and territories in the Americas, Europe, the Middle East and Africa, and Asia and the Pacific — including USD, EUR, GBP, INR, PKR, AUD, CAD, ZAR, NGN, KES, BRL, MXN, AED, SAR, JPY, CNY, PHP, IDR, VND, and the West and Central African CFA francs. The full list is published further down this page. If your browser reports a region, the matching currency is selected for you when the page loads; you can change it at any time.

No, and deliberately so. It never applies an exchange rate — the currency selector only changes how your own figures are labelled and formatted. Enter every amount in the same currency your lender quoted, and the result comes back in that currency. Since no live FX rate is involved, the figures never go stale.

Use the rate your lender or installer's financing partner has actually quoted, not a promotional teaser rate that resets later, and make sure you know whether it is a reducing-balance APR or a flat rate. Solar loan pricing varies enormously by country: rates track local policy rates, inflation, and whether the loan is secured against your property, so a rate that looks high in one market can be normal in another. Compare against other consumer loans available to you locally rather than against an international benchmark.

It depends on the market and the product. Unsecured personal and green loans are often 3 to 7 years; dedicated solar loans and property-secured financing commonly run 10, 15, 20, or 25 years. Shorter terms mean higher monthly payments but far less total interest; longer terms lower the payment while raising the total cost, so it's worth running a couple of term lengths before deciding.

A larger down payment reduces your loan amount, which lowers both your monthly payment and the total interest paid. Weigh the interest you would avoid against other uses for that cash — an emergency fund, or paying down higher-interest debt such as a credit card or overdraft, which in many markets costs considerably more than a solar loan.

Net monthly cost is your loan payment minus your estimated monthly electricity bill savings — it shows what solar actually costs (or saves) you each month, not just the loan payment in isolation. A positive net monthly cost means you're paying more than you're saving; a negative one means the system is already cash-flow positive. Enter the savings in the same currency as the loan.

No — it estimates payments on the amount you enter. Incentives differ by country: a federal tax credit in the United States, capital subsidies for rooftop systems in India, zero-rated VAT on residential installations in the United Kingdom, upfront certificate discounts in Australia, and various national or municipal grants across Europe and elsewhere. If an incentive reduces your invoice, enter the net cost; if it arrives later and you plan to put it toward the principal, run the calculator again with the reduced loan amount to see the effect.

Interest accrues on your remaining balance every month, so stretching the same amount over more payments means more months of interest charges even though each individual payment is smaller. Comparing total interest, not just the monthly payment, is the clearest way to see a loan's true cost.

No. All inputs and calculations run directly in your browser and are not sent to a server or saved in an account. General site usage may be measured through Google Analytics as described in our Privacy Policy.