Compound Interest Calculator
Estimate how savings and investments could grow over time using euros and regional assumptions.
After 20 years, your estimated balance could be
€43,987.27
You contributed €25,000.00 yourself. The remaining €18,987.27 comes from estimated compound growth. This shows how regular contributions and time can work together to build long-term value.
Balance over time
Year-by-year breakdown
| Year | Contributions | Growth | Balance |
|---|---|---|---|
| 1 | €2,200.00 | €84.16 | €2,284.16 |
| 2 | €3,400.00 | €234.03 | €3,634.03 |
| 3 | €4,600.00 | €452.95 | €5,052.95 |
| 4 | €5,800.00 | €744.47 | €6,544.47 |
| 5 | €7,000.00 | €1,112.30 | €8,112.30 |
Formula
Compound interest is calculated as A = P(1 + r/n)nt,
where P is the initial amount, r is the annual rate as a decimal,
n is the number of compounding periods per year, and t is the number of years.
With regular monthly contributions, the calculation runs iteratively period-by-period to add each contribution and apply interest.
Worked example
Starting with €1,000.00, adding €100.00 per month at 5% annual return for 20 years with monthly compounding produces an estimated final balance of €43,987.27 (€25,000.00 contributed plus €18,987.27 in compound growth).
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Frequently asked questions
What is compound interest?▾
Compound interest is interest earned on both your initial deposit and on interest already added to the balance. Over long periods, it can grow your savings far faster than simple interest.
Does this calculator account for tax in my EU country?▾
No. Tax rules vary widely across EU member states (capital gains, dividend, wealth tax). Results are pre-tax estimates only. Consult your country's tax authority or a qualified adviser.
Can I include monthly contributions?▾
Yes. Enter your regular monthly contribution and the calculator iteratively adds it to your balance each month before applying interest.
Are investment returns guaranteed?▾
No. Investment returns are not guaranteed and may go down as well as up. Rates are assumptions only — actual returns vary.