Price vs SAC Calculator
Compare Brazil’s Tabela Price and SAC on the same financed amount, term, and nominal rate. This is not a generic U.S. mortgage.
Key concepts
Tabela Price
The level-payment system used widely in Brazil. The installment stays the same; interest falls and principal rises over time. Same math as a fixed-rate U.S. principal-and-interest payment.
SAC
Sistema de Amortização Constante. Principal repayment is the same every month (amount ÷ months). The installment starts higher and declines because interest is charged on a falling balance.
What this tool does
A Brazilian comparison
Banks in Brazil commonly quote home loans as Price or SAC. This page compares those two systems only. It does not model TR, IPCA, savings-account indexers, MIP, DFI, or a CET. Switch the site currency to BRL if you want reais; the currency control changes labels, not the formula.
What to look at
Price has a flat installment and more total interest. SAC starts with a heavier installment, ends lighter, pays the balance down faster, and usually costs less interest on the same rate and term. Scenario B repeats the comparison at another amount, rate, or term — for example 30 years versus 20.
Price and SAC formulas
Monthly rate r = nominal annual rate / 12 Price installment = P × [r(1+r)^n] / [(1+r)^n − 1] SAC principal = P / n SAC installment = principal + balance × r
n is years × 12. The rate is a nominal annual rate compounded monthly, which is how many Brazilian contracts describe the interest before indexers and insurance. We do not convert an effective annual rate, and we do not add administradora fees.
Worked example
Finance 300,000 at a 10% nominal annual rate for 30 years (360 months). The Price installment stays flat. The first SAC installment is higher because the opening balance still owes a full month of interest plus 300,000 ÷ 360 of principal. By the last month, SAC’s installment is close to the principal slice alone. Total SAC interest is lower. That gap is the point of the comparison — not a promise that SAC fits your budget in year one.
Price versus SAC
Installment
- Price
- Constant
- SAC
- Starts higher, then falls
Principal each month
- Price
- Grows over time
- SAC
- Equal every month
Total interest, same rate and term
- Price
- Higher
- SAC
- Lower
| Feature | Price | SAC |
|---|---|---|
| Installment | Constant | Starts higher, then falls |
| Principal each month | Grows over time | Equal every month |
| Total interest, same rate and term | Higher | Lower |
Common mistakes
- Choosing SAC only because total interest is lower, without checking whether the first installments fit the budget.
- Treating this as a U.S. mortgage APR or PITI quote. Indexers, MIP, and DFI are outside the model.
- Entering an effective annual rate as if it were the nominal rate already divided monthly.
Methodology on this page
Price uses the standard level-payment formula. SAC amortizes principal in equal parts and charges interest on the outstanding balance. Both use nominal annual rate ÷ 12 and a term in whole years. Educational illustration of Brazilian amortization systems — not financial advice, not a CET, and not a bank simulation.
Read the full FinTools4U methodology →Frequently asked questions
Is Price the same as a U.S. fixed mortgage payment?
The principal-and-interest math matches. A U.S. mortgage payment often also bundles tax and insurance, and Brazilian contracts often add an indexer plus MIP and DFI. Those extras are not in this comparison.
Why is the first SAC payment higher?
You repay the same slice of principal every month, and the first month’s interest is charged on the full balance. As the balance falls, the installment falls with it.
Does the currency toggle change the math?
No. It only changes how amounts are displayed. Pick BRL to read the result in reais.
Is this financial advice?
No. It is a teaching comparison of two amortization systems. Your contract, indexer, and insurance decide the real installment.
Sources & further reading
- Banco Central do Brasil — Cidadania financeira — Official consumer-education home for the Brazilian financial system. Contract rates, indexers, and insurance still come from the lender.