Constant amortization, lower interest

SAC Calculator

Find out how much the installments decrease each month, how much interest you pay, and how the outstanding balance decreases in contracts using the SAC system.

When to use

  • Real estate financing with long terms.
  • Loans in which you intend to amortize in advance.
  • Situations where the goal is to reduce total interest.

Compare with other options

Simule o mesmo contrato na Calculadora Tabela Price, compare lado a lado no Comparador Price x SAC e utilize o Conversor de Taxas Equivalentes para comparar propostas de bancos.

R$
%

How is the installment calculated in SAC?

Amortization is calculated by dividing the outstanding balance by the number of installments. The installment amount results from the sum of the amortization with the interest due on the remaining balance. Thus, interest decreases as the balance reduces.

This system is preferred by investors and those who plan extra amortizations, as interest falls rapidly. The calculator shows each detailed installment so you can track the gain month by month.

Installment = (Balance / n) + (Remaining balance × rate)

n = number of installments · rate = monthly interest

Example with R$ 350 thousand in 240 installments

With a rate of 1.2% per month, the first installment is R$ 5.658,33 and the last is R$ 1.475,83. The total paid is R$ 856.100,00, with R$ 506.100,00 in interest.

InstallmentInstallment amountInterestAmortizationOutstanding balance
1R$ 5.658,33R$ 4.200,00R$ 1.458,33R$ 348.541,67
2R$ 5.640,83R$ 4.182,50R$ 1.458,33R$ 347.083,33
3R$ 5.623,33R$ 4.165,00R$ 1.458,33R$ 345.625,00
4R$ 5.605,83R$ 4.147,50R$ 1.458,33R$ 344.166,67
5R$ 5.588,33R$ 4.130,00R$ 1.458,33R$ 342.708,33
6R$ 5.570,83R$ 4.112,50R$ 1.458,33R$ 341.250,00

*Calculate the complete simulation to view all 240 installments in detail.

Benefits of SAC

Advantages

  • Lower volume of total interest paid.
  • Outstanding balance reduces rapidly.
  • Facilitates extra amortizations without surprise in installments.

Cautions

  • Higher initial installment requires cash planning.
  • Greater impact on the budget during the first months.
  • May not be ideal when income is very tight.

Analyze your cash flow and long-term goals before deciding. The calculator offers transparency to negotiate better conditions with banks and financial institutions.

Frequently Asked Questions

Select a question to see the answer.

How does the SAC system work?+
In SAC, the amortization of the outstanding balance is constant. This means that you always pay the same amortization amount plus the interest for the month. Installments start higher and gradually decrease, reducing the total interest paid over the term of the contract.
How to use this SAC calculator?+
  1. Enter the financed amount.
  2. Enter the monthly interest rate stated in the contract.
  3. Select the number of installments in months.
  4. Click on Calculate decreasing installments to generate the complete schedule.
SAC or Price Table: which to choose?+
SAC is suitable for those who can afford larger installments at the beginning and seek to pay less total interest. Price is better for those who need fixed installments. Simulate the same contract in both systems to see which fits your budget better.
How to interpret the smaller final installment?+
As amortization is constant, the outstanding balance falls faster. This decreases the amount of interest charged in each installment, resulting in smaller installments at the end of the contract.
Can I add insurance and fees to the financed amount?+
Yes. To approximate the CET (Custo Efetivo Total), add insurance, administrative fees, and IOF to the financed amount before calculating. Thus, the schedule will reflect the actual cost of the operation.