SAC table: calculate installments and interest
Enter the amount, the rate and the number of installments to see the first and last installment and the full table.
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First installment
R$9,333.33
- Last installment
- R$8,416.67
- Total interest
- R$6,500.00
- Total paid
- R$106,500.00
Your result in words
Financing R$100,000.00 over 12 months at 1% per month, the first installment is R$9,333.33 and the last is R$8,416.67. In the end you pay R$106,500.00, of which R$6,500.00 is interest.
Growth chart
| Amortization | Interest | |
|---|---|---|
| 1 | R$8,333.33 | R$1,000.00 |
| 2 | R$8,333.33 | R$916.67 |
| 3 | R$8,333.33 | R$833.33 |
| 4 | R$8,333.33 | R$750.00 |
| 5 | R$8,333.33 | R$666.67 |
| 6 | R$8,333.33 | R$583.33 |
| 7 | R$8,333.33 | R$500.00 |
| 8 | R$8,333.33 | R$416.67 |
| 9 | R$8,333.33 | R$333.33 |
| 10 | R$8,333.33 | R$250.00 |
| 11 | R$8,333.33 | R$166.67 |
| 12 | R$8,333.33 | R$83.33 |
Detailed breakdown
| Installment | Amount | Interest | Amortization | Outstanding balance |
|---|---|---|---|---|
| 1 | R$9,333.33 | R$1,000.00 | R$8,333.33 | R$91,666.67 |
| 2 | R$9,250.00 | R$916.67 | R$8,333.33 | R$83,333.33 |
| 3 | R$9,166.67 | R$833.33 | R$8,333.33 | R$75,000.00 |
| 4 | R$9,083.33 | R$750.00 | R$8,333.33 | R$66,666.67 |
| 5 | R$9,000.00 | R$666.67 | R$8,333.33 | R$58,333.33 |
| 6 | R$8,916.67 | R$583.33 | R$8,333.33 | R$50,000.00 |
| 7 | R$8,833.33 | R$500.00 | R$8,333.33 | R$41,666.67 |
| 8 | R$8,750.00 | R$416.67 | R$8,333.33 | R$33,333.33 |
| 9 | R$8,666.67 | R$333.33 | R$8,333.33 | R$25,000.00 |
| 10 | R$8,583.33 | R$250.00 | R$8,333.33 | R$16,666.67 |
| 11 | R$8,500.00 | R$166.67 | R$8,333.33 | R$8,333.33 |
| 12 | R$8,416.67 | R$83.33 | R$8,333.33 | R$0.00 |
Informational estimate, without fees or inflation. Check taxes and charges for your case; the real result may differ.
How it works
What is SAC
In SAC (constant amortization system) you pay down the same part of the debt every month, and interest applies to a shrinking balance. That is why the installment starts higher and keeps dropping.
SAC or Price?
SAC usually costs less interest in total, but needs a higher first installment. If your budget is tight at the start, compare with the Price table.
Formula
How to calculate
A is the constant amortization, P the financed amount, n the number of installments and i the monthly rate. The installment of month k adds the amortization to the interest on the balance S, which drops by exactly A each month.
Example
With round numbers, so you can check the math:
Financing R$100,000.00 over 12 months at 1% per month, the first installment is R$9,333.33 and the last is R$8,416.67. In the end you pay R$106,500.00, of which R$6,500.00 is interest.
Frequently asked questions
Why does the SAC installment go down?
Because the amortization is fixed and interest falls along with the outstanding balance. Adding the two parts, each installment is smaller than the previous one.
Is SAC always cheaper than Price?
With the same rate and term, yes: the balance drops faster and generates less interest in total. The difference is the first installment, which is higher.
Does the table include insurance and fees?
No. The calculator only considers the amount financed, the rate and the term. Insurance, fees and TR (reference rate) adjustment can raise the real installment.
Math checked by the JuntaTudo team · updated on Nov 12, 2026
