Investment Return Calculator
Model your investment growth by entering an initial amount, monthly contributions, expected annual return, and time horizon. See a year-by-year projection of your portfolio value.
Final Portfolio Value
$343,778.24
Total Contributions
$130,000.00
Investment Returns
$213,778.24
Year-by-Year Growth
How to use
Enter your initial investment amount, the amount you plan to contribute each month, your expected annual rate of return (the S&P 500 has historically averaged about 10% before inflation), and the number of years you plan to invest. The calculator shows your projected total value, how much came from your contributions, and how much came from investment returns.
Formula
This combines the future value of a lump sum with the future value of an annuity (regular contributions). P is the initial investment, PMT is the monthly contribution, r is the monthly return rate, and nis the total number of months. Each monthly contribution compounds from the time it's made until the end of the investment period.
When this calculator helps
Whether you are just starting to invest or reviewing an existing portfolio, this calculator helps you visualize long-term growth and set realistic expectations. First-time investors can see how small monthly contributions compound into significant wealth over decades. Financial planners use it to model different scenarios, varying contribution amounts, return rates, and time horizons, to build personalized investment strategies. It is also useful for couples planning major life goals like retirement, college funds, or a home purchase, helping them understand exactly how much to set aside each month.
Examples
Example 1: New Graduate Starting Early
A 22-year-old invests $5,000 initially and contributes $300 per month at an average 8% annual return. After 40 years at age 62, the portfolio grows to approximately $1,050,000, despite only contributing $149,000 out of pocket. Starting early lets compounding do the heavy lifting.
Example 2: Mid-Career Catch-Up
A 40-year-old with $50,000 saved begins contributing $1,000 per month at 7% annual return. By age 65, the portfolio reaches roughly $870,000. The $50,000 head start grows to $271,000 on its own, while the monthly contributions add another $599,000 with interest.
Example 3: Conservative Bond Portfolio
An investor places $100,000 in a bond fund returning 4% annually with no additional contributions. After 20 years, the investment grows to about $219,000. While slower than stocks, bonds provide stability, the portfolio never experienced the 30-40% drops possible in equity markets.
Things to watch
- •Use a conservative return estimate (6-7% after inflation) rather than optimistic projections to avoid overestimating your future wealth.
- •This calculator assumes consistent returns, but real markets fluctuate, actual results will vary year to year even if the long-term average holds.
- •Investment fees of 0.5-1% annually can reduce your final balance by 10-20% over 30 years. Factor in expense ratios when choosing your expected return.
- •Tax-advantaged accounts (401k, IRA, Roth IRA) let your investments grow tax-free or tax-deferred and can improve long-term results.
- •Increase your monthly contribution by at least 1% each year if you can. Small bumps to your savings rate can matter a lot over decades.
Sources and methodology
Last reviewed: April 25, 2026. We review formulas, default assumptions, and examples against public references when a formal source applies.
Method: This calculator uses the formula explained on this page, then checks default assumptions and examples against the references listed below.
- •Compound Interest Calculator, Investor.gov
- •What is compound interest?, Investor.gov
Found something off? Send a correction with the page URL, inputs, result, and expected result.
Common questions
- What is a good annual return on investment?
- The S&P 500 has historically returned about 10% annually before inflation (roughly 7% after inflation). A "good" return depends on the investment type: savings accounts yield 4-5%, bonds 4-6%, stocks 7-10%, and real estate 8-12% on average.
- How do regular contributions affect investment growth?
- Regular contributions dramatically accelerate growth through dollar-cost averaging. Investing $500/month at 8% for 30 years turns $180,000 in contributions into approximately $745,000, the majority of your wealth comes from investment returns, not the money you put in.
- What is the difference between nominal and real returns?
- Nominal return is the raw percentage your investment gains before adjusting for inflation. Real return subtracts inflation (typically 2-3% per year) to show your actual purchasing power growth. If your portfolio gains 10% in a year with 3% inflation, your real return is roughly 7%.
- How does compounding frequency affect my returns?
- More frequent compounding (daily vs. annually) produces slightly higher returns because interest earns interest sooner. However, the difference is small, $10,000 at 8% for 10 years yields $21,589 with annual compounding versus $22,255 with daily compounding. The bigger factor is your rate of return and time horizon.
- Should I invest a lump sum or spread it out over time?
- Historically, lump-sum investing outperforms dollar-cost averaging about two-thirds of the time because markets tend to rise. However, spreading investments over 6-12 months reduces the risk of investing everything at a market peak and can be psychologically easier for large amounts.