Investing & Finance

Compound Interest Calculator

Final capital, deposits and income – with a history table.

Updated on Apr 21, 2026 Calculator, calculation path and examples on one page

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Calculator

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Calculation path

Step by step

  1. Determine interest rate per interval

    Formula: i = annual interest rate / intervals

    Values inserted: 4.50% / 12

    Result: 0.375%

  2. Determine running time in intervals

    Formula: n = years × intervals

    Values inserted: 12.0×12

    Result: 144

  3. Calculate final capital

    Formula: K = K0 × (1 + i)^n + R × (((1 + i)^n − 1) / i)

    Result: €17,142.75

course per year

Year capital
1 €10,459.40
2 €10,939.90
3 €11,442.48
4 €11,968.14
5 €12,517.96
6 €13,093.03
7 €13,694.52
8 €14,323.65
9 €14,981.67
10 €15,669.93
11 €16,389.80
12 €17,142.75

Instructions

How to use this calculator correctly

How to use the calculator

  • Enter starting capital, interest rate and term.
  • Optionally add regular deposits.
  • Choose the interval that suits the interest rate.

How to read the result

  • Final capital shows the total value at the end.
  • Income is the difference between final capital and deposits.

Limits of the calculation

  • Taxes, fees and exchange rate fluctuations are not included here.

Related guide: ETF, savings plan and compound interest simply explained

Examples

Typical calculations

10,000 euros at 4.5 percent for 12 years.

Without deposits

Final capital: €16,958.81

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5,000 euros, 100 euros per month.

With monthly rate

Final capital: €37,297.41

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20,000 euros, 250 euros per quarter.

Quarterly

Final capital: €36,364.56

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FAQ

Frequently asked questions

What is compound interest?

Interest is added to the capital and interest is paid again in the next period.

Can I consider regular deposits?

Yes, you can enter a fixed amount per interest interval.

What happens at 0 percent interest?

Then the calculator only adds up starting capital and deposits.

Why is monthly interest stronger than annual interest?

Because the interest is credited more frequently and interest is charged again.

Is the result guaranteed?

No, the calculator only depicts a mathematical scenario.

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Sources and notes

Rule status and context

Formula
K = K0 × (1 + i)^n + R × (((1 + i)^n − 1) / i)