Loan Simulator: Price vs SAC

Compare the two most widely used amortization systems side by side: monthly payment amounts, principal balance evolution, and total interest paid by the end of the loan.

                        interest difference (price − sac)
                        $ 0.00
                    

Price Schedule (fixed payment)

1st installment -

last installment -

total interest -

Total paid at the end: -

month	installment	interest	remaining balance

SAC (constant amortization)

1st installment -

last installment -

total interest -

Total paid at the end: -

month	installment	interest	remaining balance

Price Schedule: fixed monthly payments

In the Price Schedule (also known as the French Amortization System), payments are structured to remain equal from the first to the final month. Early on, most of the payment goes toward interest while a smaller portion reduces the principal balance. Over time, this proportion reverses, but the total monthly payment amount never changes.

SAC: constant principal amortization

Under SAC (Constant Amortization System), the principal portion paid off each month remains fixed rather than the total monthly payment. Because the remaining balance declines faster in the early months, interest charges decrease progressively, causing overall monthly payments to start higher and end lower than in the Price Schedule.

Which system to choose

If your budget is tight at the start, the Price Schedule can help due to lower initial monthly payments. However, if your goal is to pay less interest overall and your income allows for higher initial installments, SAC tends to be more advantageous—especially for long-term loans like home mortgages.

Frequently asked questions

What is the difference between Price Schedule and SAC?

With Price, all payments remain equal. With SAC, principal amortization is constant while interest decreases each month, meaning payments start higher and finish lower.

Which system pays less total interest, Price or SAC?

SAC generally incurs less total interest because the principal drops faster early on, though initial payments are higher.

Which system is most commonly used for mortgages?

SAC is the standard for most housing loans in Brazil. The Price Schedule is more commonly applied to vehicle loans and short-term credit.