Project the future value of any investment with compound growth. Enter a lump sum, add optional monthly contributions, and see your returns grow year by year.
Results update live as you type.
Future Value
Future Value
$144,573
after 20 years
Total Invested
$58,000
principal + contributions
Total Returns
$86,573
interest earned
ROI
149.3%
return on investment
| Year | Balance | Invested | Interest |
|---|
The Formula
Investment growth is modelled using the future value of an annuity formula. The initial lump sum compounds at the annual return rate, while each monthly contribution is compounded separately. The two results are added together to give the total projected portfolio value. The key insight is that compounding is non-linear — returns earned in early years generate their own returns, accelerating growth exponentially over time.
Future Value Formula
About This Tool
An investment calculator — also called a future value calculator or compound growth calculator — projects how much money an investment will be worth over a specific time period, given an expected annual return rate and optional ongoing contributions. It is one of the most useful financial planning tools available, helping investors understand the long-term impact of their savings habits and investment choices.
Our investment growth calculator uses the future value of an annuity formula to model compound growth monthly. This means interest is calculated and added to the balance each month, not just once a year — which produces more accurate results than simple annual compounding. The result is your projected portfolio value at the end of the investment horizon.
Use this tool to compare lump-sum investing vs. dollar-cost averaging with monthly contributions, model different return rate scenarios, understand the impact of starting early vs. starting late, and project long-term wealth accumulation for retirement, education, or other financial goals.
The year-by-year schedule and breakdown chart give you full transparency into how your balance grows and what proportion comes from your contributions vs. compounded returns — showing the power of compound interest in concrete dollar terms.
Monthly Compounding
Uses precise monthly compounding, not simplified annual compounding.
ROI Calculation
Shows total return on investment as a percentage alongside dollar growth.
Growth Chart
Visualise the exponential curve of compound growth year by year.
Flexible Periods
Quick toggle for 10, 20, or 30-year horizons with live recalculation.
100% Private
No account needed. All calculations run locally in your browser.
Breakdown Detail
See exactly how much of your final value is principal vs. compounded returns.
Four inputs give you a complete investment projection in seconds.
Type or slide the lump sum amount you're investing today. This is the principal that starts compounding immediately.
Optionally enter a monthly contribution — a regular investment amount added each month, such as automatic transfers to a brokerage account or IRA.
Enter the expected annual return. Use 7% for a balanced historical average, 5% for conservative, or 9–10% for a growth-focused equity portfolio.
Toggle between 10, 20, or 30 years to see how dramatically the time horizon affects your outcome. Longer periods unlock the full power of compounding.
The Over Time chart shows the compound growth curve vs. contributions. Notice how the gap between total invested and future value widens dramatically over time.
Switch to the Breakdown tab to see the exact split between your principal, contributions, and interest earned — and the Schedule tab for a year-by-year balance table.
Future value
A lump sum grows by the future value formula FV = P × (1 + r)t. The table below assumes a steady 7% annual return, compounded yearly, with no further deposits and before taxes and fees. Real markets don't return a steady 7%, so treat these figures as a planning baseline, not a forecast.
| Starting amount | After 10 years | After 20 years | After 30 years |
|---|---|---|---|
| $10,000 | $19,672 | $38,697 | $76,123 |
| $20,000 | $39,343 | $77,394 | $152,245 |
| $200,000 | $393,430 | $773,937 | $1,522,451 |
| $250,000 | $491,788 | $967,421 | $1,903,064 |
Money in 20 years buys less than money today. A common shortcut is to use a real return: your expected return minus expected inflation. At 7% nominal and 2.5% inflation, the real return is roughly 4.5%. At that rate, $200,000 grows to about $482,343 in today's dollars after 20 years, compared with $773,937 in future dollars.
Rule of 72: divide 72 by the annual return to estimate how many years it takes to double. At 7%, money doubles about every 10.3 years, which is why $10,000 becomes roughly $20,000, $40,000 and $80,000 by years 10, 20 and 30.
To add monthly contributions, use the compound interest calculator. To test whether your savings will last in retirement, use the retirement calculator. To solve for any single unknown, use the TVM finance calculator.
Everything you need to know about investment growth and this calculator.
Compound interest means you earn returns not just on your original investment but on all previously earned returns as well. This creates an exponential growth curve rather than linear growth. For example, at 7% annual return, $10,000 grows to ~$19,672 after 10 years, $38,697 after 20 years, and $76,123 after 30 years — not just $10,000 more every decade, but doubling and doubling again. This is why starting early is so powerful.
The Rule of 72 is a quick mental calculation to estimate how long it takes for an investment to double: divide 72 by the annual return rate. At 7% return, money doubles in 72 ÷ 7 ≈ 10.3 years. At 10% it doubles in 7.2 years. At 4% it takes 18 years. This rule helps you quickly compare investment scenarios without a calculator and shows why higher returns have such a dramatic effect over long time horizons.
The S&P 500 has returned approximately 10% annually on average since 1957, before inflation. After inflation (about 3% historically), the real return is ~7%. A balanced portfolio (60% stocks, 40% bonds) has returned ~8–9% nominal. For planning purposes, financial advisors often use 6–7% as a conservative nominal estimate to account for the fact that future returns may be lower than historical averages. Always use nominal returns in this calculator — not inflation-adjusted — unless you also inflate your target.
Research consistently shows that lump-sum investing outperforms dollar-cost averaging (DCA) about two-thirds of the time, because markets tend to rise over time. However, DCA reduces timing risk and is the only practical option for most people who invest from monthly income. The best approach is often both: invest any lump sum immediately, then continue with regular monthly contributions. Use this calculator to model both approaches and see the combined effect.
This calculator does not model taxes. In a tax-deferred account like a 401(k) or traditional IRA, your full returns compound without annual tax drag, but you pay income tax on withdrawals. In a Roth account, you pay no tax on withdrawals after 59½. In a taxable brokerage account, you may owe capital gains taxes on dividends and realised gains annually. For long-term compound growth projections, tax-advantaged accounts are significantly more efficient — consider filling these before taxable accounts.
This calculator is mathematically exact for the constant return rate you enter. Real-world investment returns are variable — markets fluctuate year to year, and actual returns will differ from projections. The results should be used for scenario planning and directional guidance, not precise forecasting. For a more realistic projection, consider running multiple scenarios with different return assumptions (pessimistic at 4–5%, base at 7%, optimistic at 9–10%) to understand the range of possible outcomes.
Results are estimates for education and planning. They are not financial, tax or legal advice. Rates, fees and tax rules change, so confirm the figures with your lender, the IRS or a qualified professional before you make a decision.
Spotted an error or out-of-date figure? Tell us. We review every report and correct confirmed mistakes promptly.