Loan Calculator

How it works

With the Price Table, every installment comes out at the same value from start to finish. SAC (Constant Amortization System) works with fixed amortization, so the installments shrink over time and the total interest you pay ends up lower.

The math here runs on monthly compound interest. Treat the figures as estimates and check the exact terms with your own financial institution.

Price table vs. SAC: the two dominant amortization systems in Brazil

A loan amortization schedule splits each instalment into interest (on the outstanding balance) and principal amortization. The two systems used for Brazilian mortgages and consumer loans are the Price table (French system, fixed instalments) and SAC (Sistema de Amortização Constante — constant principal). In Price, the instalment is constant and computed by PMT = PV · i / (1 − (1+i)⁻ⁿ); interest starts high and falls while amortization grows. In SAC, principal amortization is fixed (A = PV / n), interest falls each month and instalments decrease. Example: a R$ 300,000 loan over 360 months at 10% per year (≈ 0.7974% per month) gives a Price instalment of ~R$ 2,632 (constant); SAC starts at ~R$ 3,326 and ends near R$ 840. SAC pays less total interest because it amortizes principal faster.

Brazilian context: SFH, SFI, CET and TR

Mortgages in Brazil fall under the SFH (Sistema Financeiro da Habitação, Law 4,380/1964) for properties up to a capped value with regulated rates, or SFI (Sistema de Financiamento Imobiliário, Law 9,514/1997) for free-market terms. Caixa Econômica Federal, the largest housing lender, has used SAC by default for property loans since 2018. Rates are typically nominal interest + TR (Taxa Referencial, often zero). Resolution BCB 3,517/2007 requires lenders to disclose the CET (Custo Efetivo Total): the all-in effective annual rate including insurance, registration fees and administrative charges — always compare CET, not just the headline rate.

FAQ

Which is cheaper, Price or SAC? SAC pays less total interest because the balance falls faster, but starting instalments are higher. Price is easier to budget — same payment every month.

What rate do I enter, monthly or annual? Brazilian mortgage rates are usually quoted as annual nominal; convert to monthly with i_m = (1 + i_a)^(1/12) − 1. This tool expects monthly rate.

Does the simulation include insurance and fees? No — only principal and interest. The real instalment also includes MIP/DFI insurance and administrative charges; the CET reflects that.

Is it worth prepaying? Generally yes for SAC (cuts more future interest), and in Price you can shorten the term or reduce the instalment. Brazilian law forbids prepayment penalties on regulated mortgages.