Codex Tools
pt
How is it calculated?Terminal

Price vs SAC Loan Simulator

Compare monthly payments, total interest and balance evolution between Price (fixed payment) and SAC (constant amortization), including extra monthly principal payments.

The link keeps what is on screen.
Parameters
Loan parameters

SAC System (Decreasing)

1st payment
R$ 3.339,88
Last payment
R$ 840,30
Total interest
R$ 452.433,49
Total paid
R$ 752.432,29
Effective term
360 / 360

Price Table (Fixed)

1st payment
R$ 2.638,52
Last payment
R$ 2.638,52
Total interest
R$ 649.871,06
Total paid
R$ 949.867,20
Effective term
360 / 360

First 12 installments

Sistema
MonthPaymentPrincipalInterestBalance
#1R$ 3.339,88R$ 833,33R$ 2.506,55R$ 299.166,67
#2R$ 3.332,91R$ 833,33R$ 2.499,58R$ 298.333,34
#3R$ 3.325,95R$ 833,33R$ 2.492,62R$ 297.500,01
#4R$ 3.318,99R$ 833,33R$ 2.485,66R$ 296.666,68
#5R$ 3.312,03R$ 833,33R$ 2.478,70R$ 295.833,35
#6R$ 3.305,06R$ 833,33R$ 2.471,73R$ 295.000,02
#7R$ 3.298,10R$ 833,33R$ 2.464,77R$ 294.166,69
#8R$ 3.291,14R$ 833,33R$ 2.457,81R$ 293.333,36
#9R$ 3.284,18R$ 833,33R$ 2.450,85R$ 292.500,03
#10R$ 3.277,21R$ 833,33R$ 2.443,88R$ 291.666,70
#11R$ 3.270,25R$ 833,33R$ 2.436,92R$ 290.833,37
#12R$ 3.263,29R$ 833,33R$ 2.429,96R$ 290.000,04
How is it calculated?
Converts the effective annual rate to a monthly rate via compound interest: (1 + annual_rate)^(1/12) − 1. Under Price, the base payment is constant while principal amortization grows over time; under SAC, monthly principal amortization is constant (principal ÷ months) and interest decreases every month.
See the code ↗

Processed in your browser; nothing is sent.

Use from the terminal (JSON)

This tool also runs outside the site: the cli.js script uses the same logic as this page and returns the result as JSON. Parameters are the same as this page's URL — copy the command below with the values on screen.

Deno
deno run -q "https://tools.thecodecodex.com/cli.js?tool=loan-simulator"
Node.js / Bun
curl -s https://tools.thecodecodex.com/cli.js | node --input-type=module - loan-simulator valor=…
ParameterDescriptionDefault
valorvalor financiado (R$)300000
taxataxa de juros efetiva anual (fração, ex.: 0.105 = 10,5% a.a.)0.105
mesesprazo em meses360
extraamortização extra mensal opcional (R$)0

Requires Deno, Node.js or Bun. With Deno the script runs with no permissions: it cannot read files or access the network. Central Bank indicators are from the day the site was published.

More in Finance