Calculadora de Juros Compostos
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
Formula
VF = P·(1+i)ⁿ + PMT·[((1+i)ⁿ − 1) / i]
About this calculator
The Compound Interest Calculator computes the final amount of an investment or debt that grows at a compound interest rate. It uses the formula M = P * (1 + i)^n, where M is the final amount, P is the principal, i is the interest rate per period, and n is the number of periods. Compound interest means interest is calculated on the accumulated amount, including previous interest, leading to exponential growth over time.
To use the calculator, enter the principal (P), the interest rate (i) as a percentage per period, and the number of periods (n). The calculator returns the final amount and, in some versions, the total interest earned. Ensure the rate and period are in the same time unit (monthly, yearly, etc.). For example, if the rate is 2% per month, the period should be in months.
This tool is useful for simulating investments like savings accounts, CDs, or stocks, or calculating debt growth such as loans or credit card balances. It also helps with financial planning, like saving for a future goal. Remember that real-world rates and terms may vary, and it's essential to consider inflation and taxes.
Common pitfalls: do not confuse simple interest with compound interest (the latter grows exponentially). Verify that the rate and period are consistent. Avoid premature rounding, as small rate differences can lead to large long-term variations. The calculator assumes a constant rate, which rarely occurs in practice.
Frequently asked questions
What is the difference between simple and compound interest?
In simple interest, interest is calculated only on the principal. In compound interest, interest is calculated on the accumulated amount, generating interest on interest, which accelerates growth.
How to convert an annual rate to a monthly rate for compound interest?
Use the formula: monthly rate = (1 + annual rate)^(1/12) - 1. For example, 12% per year equals approximately 0.949% per month.
Does the compound interest calculation consider monthly contributions?
No, this calculator considers only a fixed initial amount. For periodic contributions, you need a specific annuity calculator.
Can I use the calculator to compute the amount of a loan?
Yes, but remember that loans often have different rates and terms, and may include other fees. The calculator provides a basic estimate.
What does 'period' mean in the calculator?
Period is the number of times interest is applied, such as months, years, or days. It must be in the same unit as the interest rate.