Project the future value of your savings or investments with compound interest, regular contributions, and any rate.
Enter your investment parameters on the left to see how compound interest can help your money grow
Your initial investment earns interest, which is added to your principal.
Interest starts earning interest, creating exponential growth over time.
Monthly investments significantly accelerate your wealth building.
Future value of $10,000 invested today, compounded annually, at common long-term return rates:
| Annual return | 10 years | 20 years | 30 years | 40 years |
|---|---|---|---|---|
| 5% | $16,289 | $26,533 | $43,219 | $70,400 |
| 7% | $19,672 | $38,697 | $76,123 | $149,745 |
| 9% | $23,674 | $56,044 | $132,677 | $314,094 |
| 10% | $25,937 | $67,275 | $174,494 | $452,593 |
Assumes annual compounding, no additional contributions, no taxes. Real returns after inflation are typically 1-2% lower. Use the calculator above to model monthly contributions and taxes.
The future value of an investment earning compound interest is calculated with the standard formula:
FV = P × (1 + r/n)^(n×t) + PMT × [((1 + r/n)^(n×t) − 1) / (r/n)]Where:
Worked example (the $10,000 → $76,123 number above):
P = 10000, r = 0.07, n = 1 (annual compounding), t = 30, PMT = 0 FV = 10000 × (1 + 0.07)^30 = 10000 × 7.6123 = $76,123The same $10,000 compounded monthly (n = 12) instead of annually grows to $81,150 — a $5,027 difference from twelve more compounding events per year. This is why banks promote “daily compounding”: the math advantage compounds in the bank's favor.
Mei is 30, earns $65,000/year, and wants to retire at 65. She opens a Roth IRA with a $3,000 starting balance, contributes $400/month, and invests in a low-cost S&P 500 index fund with a long-run average return of about 7% after inflation (≈ 10% nominal, 3% inflation).
Mei can withdraw 4% per year (≈ $23,700) and historically never run out — the canonical 4% rule for retirement planning. Try Mei's numbers in the calculator above to see how adjusting her monthly contribution by even $50 changes the outcome.
Calculator formulas use the standard compound interest formula with periodic contributions. Past market performance does not guarantee future returns.
Every CalcCentral calculator is authored by a credentialed subject-matter expert and independently reviewed before publication. Our editorial policy follows the same E-E-A-T guidelines used by Google to evaluate YMYL (your-money-or-your-life) pages.
Author
Maya Chen, CFA
Chartered Financial Analyst
Independently reviewed
Dr. Aaron Pak, PhD
Doctor of Kinesiology & Public Health
Last reviewed: August 12, 2026 · Next scheduled review: quarterly
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FAQ
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It depends on the rate and time. $10,000 at 7% for 30 years with monthly compounding grows to $81,169. At 10% for 40 years, it grows to $452,593. Our compound interest calculator lets you enter any principal, rate, and time to see the exact future value. The compound interest calculator results show how much is from contributions vs interest earned.
How it works
Our compound interest calculator lets you project the future value of an investment with regular contributions and compound growth in five steps.
Type the amount you have already saved or invested. Use 0 if you are starting from scratch.
Type the expected annual return as a percentage. A diversified stock portfolio has historically returned about 7% after inflation.
Type how many years you plan to let the money grow. Compound interest is most powerful over long horizons.
Type how much you add each month. Even small regular contributions compound dramatically over decades.
The calculator shows the final balance, total contributions, interest earned, and a year-by-year growth table.
Learn how compound interest works, why it's so powerful, and how to harness its power for wealth building.
Understand how the time value of money principle underlies compound interest and all financial calculations.
Learn how much you need for retirement using the 4% rule, inflation adjustments, and Social Security estimates.