Home › Investment Calculator
Investment Calculator
Enter your initial amount, monthly contributions, expected annual return, and time horizon to see how your investments could grow over time.
Results (estimates only — not financial advice)
How the calculation works
The calculator uses the future value formula for an annuity with an initial lump sum. Each month, the existing balance earns the periodic rate (annual rate divided by compounding periods), and your contribution is added. The formula for compound growth with regular contributions is:
FV = P × (1 + r/n)n×t + PMT × [((1 + r/n)n×t − 1) / (r/n)]
Where P = initial investment, r = annual rate, n = compounding periods per year, t = years, PMT = periodic contribution.
These are estimates only and do not account for taxes, fees, inflation, or market volatility. Consult a financial adviser before making investment decisions.
Frequently asked questions
What is a realistic annual return for investments?
The S&P 500 has historically averaged about 10% per year before inflation, or roughly 7% after inflation. Bond portfolios typically return 3-5% per year. A balanced 60/40 portfolio has historically returned around 7-8% before inflation. Past performance does not guarantee future results.
How does compounding affect investment growth?
Compounding means you earn returns on previously earned gains, not just your original investment. Over long periods this dramatically accelerates growth. $10,000 at 7% per year becomes about $76,000 in 30 years without any additional contributions.
How much should I invest each month?
Most financial planners recommend investing at least 15% of gross income for retirement. Even small amounts matter due to compounding. Starting earlier is more important than the amount, since time is the biggest driver of investment growth.
What is the difference between nominal and real return?
Nominal return is the raw percentage gain. Real return adjusts for inflation, showing actual purchasing-power gain. If your investment grows 8% per year but inflation is 3%, your real return is approximately 5%. Subtract expected inflation from the rate field for a rough real-return estimate.
Should I invest a lump sum or monthly?
Research shows lump-sum investing outperforms dollar-cost averaging about two-thirds of the time, since markets tend to rise over time. However, regular monthly contributions reduce timing risk and build a consistent savings habit. Both strategies can work well.