毎月の積立で投資が指数関数的に成長する様子を可視化。
左側のパラメータを入力し、複利がお金を増やす仕組みを確認してください
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.
月500ドルの積立、月次複利：
| 年数 | 積立合計 | 利息 | 最終残高 |
|---|---|---|---|
| 10年 | 6万ドル | 2.95万ドル | 8.95万ドル |
| 20年 | 12万ドル | 17.2万ドル | 29.2万ドル |
| 30年 | 18万ドル | 61万ドル | 79万ドル |
72の法則：72÷金利=倍になる年数。7%なら10.3年で倍に。S&P 500は歴史的に名目10% / 実質7%。
Cross-checked against authoritative formulas (IRS, NIST, ACSM) and updated for 2025/2026 tax years and rates.
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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.
See how your savings grow over time with monthly contributions.
Estimate returns on lump-sum or periodic investments over time.
Project the future value of a present sum at a given rate.
Find the present value of a future sum of money at a given rate.
Find the annual percentage yield on a savings account or CD.
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