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Compound Interest Calculator

Find out how much your money can grow over time. Enter the initial amount, monthly contribution, interest rate and period — and watch the compounding snowball effect on an interactive chart, with a month-by-month breakdown.

📊 Dados do investimento

≈ 12.68% ao ano
5 anos e 0 meses
💎 Montante final
R$ 18.150,63
💵 Total investido
R$ 13.000,00
🔥 Juros acumulados
R$ 5.150,63
+39.6% sobre investido
R$ 0R$ 5kR$ 9kR$ 14kR$ 18k
Montante total Total investido

Responsible use

How to verify the result

A useful tool should let you verify its output. Start with a small test, keep the original and only then use the result in production. The scenario below helps catch problems before you copy, download or share anything.

Practical check

Try 1,000, a 1% monthly rate and 12 months; compare the amount with M = P × (1 + r)ⁿ.

What this tool does not replace

This is an educational estimate based on your inputs. It does not automatically include every contract rule, tax, fee or legal change; confirm financial decisions with official documents and sources.

Data handling

Primary content is processed in your browser and is not sent to the UseHubTools server. Local data may remain in browser storage until you clear it.

Content reviewed on August 11, 2026.

How compound interest works

Compound interest is "interest on interest": each period, the return is calculated on the accumulated balance (principal + previous interest), not only on the initial amount. The formula is M = C × (1 + i)ⁿ.

That is why time is the investor's greatest ally — the earlier you start, the bigger the exponential effect.

Time and consistency win

Regular monthly contributions, even small ones, make a huge difference. Reinvesting returns instead of withdrawing them is what makes wealth grow exponentially.

How to use the calculator

Fill in the initial amount, the monthly contribution, the monthly interest rate and the period in months or years. The result shows the final amount, the total invested and the accumulated interest, plus a chart and a month-by-month breakdown so you can visualize the growth over time.

Frequently asked questions

Is the rate monthly or yearly?

The main field uses the monthly rate. The equivalent yearly rate is shown automatically below it.

Is anything saved on a server?

No. Everything is calculated in your browser in real time. Nothing is uploaded.

Does it work for any fixed-income product?

Yes. Use the estimated net monthly rate of the investment to simulate any product with contributions.

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