Investment Calculator
Investment calculators project portfolio growth using compound interest. Formula: FV = PV(1+r)^t for lump sum, or FV = PMT × [((1+r)^t - 1) / r] for regular contributions. For example, $10,000 initial investment at 8% annual return grows to $46,610 in 20 years. Adding $200/month increases it to $164,745. Adjust for inflation, fees, and tax implications. Historical stock market average: 10% annually, bonds: 5-6%.
Calculate investment growth over time with monthly contributions. See projected returns, total invested, and year-by-year breakdown.
Initial Investment
$
Monthly Investment
$
Expected Annual Return
%
Investment Period
years
Inflation Rate (optional)
%
Future Value
$343,778.24
Total Invested
$130,000.00
Total Returns
$213,778.24
Investment Growth
38%
62%
Principal Returns
Investment Tips
- Historical S&P 500 average return: ~10% annually (before inflation)
- Start early - time in the market beats timing the market
- Consider diversification across asset classes
- Account for inflation when setting return expectations
How to Use
- Enter your value in the input field
- Click the Calculate/Convert button
- Copy the result to your clipboard
Frequently Asked Questions
- How do I calculate investment returns?
- Investment returns are calculated using compound interest: Future Value = P(1 + r)^t where P = principal, r = annual return rate, t = years. With monthly contributions, each deposit compounds from its addition date. A $10,000 investment at 8% for 20 years grows to ~$46,610.
- What is a realistic annual return rate?
- Historical S&P 500 average return is about 10% annually before inflation (7% after). Conservative portfolios: 4-6%. Moderate: 6-8%. Aggressive: 8-12%. Individual stocks vary widely. Past performance does not guarantee future results.
- How do monthly contributions affect investment growth?
- Regular contributions dramatically boost returns through dollar-cost averaging. $500/month at 8% for 30 years = $745,180 (you contributed $180,000, earned $565,180). Starting early matters more than contribution size due to compound growth.
- What is the Rule of 72?
- The Rule of 72 estimates how long money takes to double: 72 ÷ interest rate = years to double. At 8% return: 72÷8 = 9 years to double. At 6%: 12 years. At 12%: 6 years. Simple approximation for compound growth.
- How does inflation affect investment returns?
- Inflation reduces purchasing power of future money. A 10% return with 3% inflation = ~7% real return. $100 today at 3% inflation = $74 purchasing power in 10 years. Investments should outpace inflation to grow real wealth.