Compound interest calculator
Projects a balance that starts from an initial amount, receives a fixed contribution at the start of every month and grows at a constant annual rate compounded monthly.
Parameters
10
Total Future Value
28,124 €
Total Invested
19,000 €
Interest Earned
+9,124 €
Indicative results for educational purposes only. They rely on simplified assumptions (constant returns, no taxes, fees or inflation unless stated) and do not constitute financial, tax or investment advice. Past performance does not guarantee future results; consult a qualified professional before making decisions.
How it calculates
each month: balance = (balance + contribution) × (1 + r / 12)
- Inputs: initial amount, monthly contribution, annual rate (%) and number of years.
- Compounding is always monthly; there is no frequency selector.
- The chart separates what was paid in (initial amount + contributions) from the interest accumulated at the end of each year.
Example with the default values
Initial 1,000 · contribution 150/month · 7% per year · 10 years
→ Paid in 19,000 · interest ≈ 9,124 · final balance ≈ 28,124
Limitations
- It does not adjust for inflation: to get a result in today’s purchasing power, enter a real rate.
- It does not model fees, taxes or volatility; the rate is identical every month.
- It is a calculation tool, not an investment recommendation.