Investment Calculator

Calculate compound interest, future value, and growth of your investments over time.

計算機

結果

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How Compound Interest Multiplies Wealth

Compound interest occurs when the interest you earn begins generating its own interest over time. Combined with regular monthly contributions, the power of compounding allows relatively modest savings to accumulate substantial wealth across a 10, 20, or 30-year horizon.

This free investment calculator computes the future value of your portfolio, total contributions, and cumulative interest earned, and also factors in purchasing power by estimating the impact of inflation.

使い方

Compound interest is interest earned on both the initial principal and the accumulated interest from previous periods. It allows your money to grow exponentially over time.

仕組み

Calculate compound interest, future value, and growth of your investments over time.

公式 / 計算方法

This calculator uses standard mathematical formulas for accurate results.

例

Try the calculator above with your own values to see personalized results.

よくある質問

What is compound interest?

Compound interest is interest earned on both the initial principal and the accumulated interest from previous periods. It allows your money to grow exponentially over time.

How does inflation affect investment returns?

Inflation reduces the purchasing power of your returns. Real return = nominal return - inflation rate. Always consider inflation when planning long-term investments.

What if I invest regularly for the future?

This investment calculator lets you run "what if" scenarios: enter an initial amount, add a monthly contribution, choose an expected annual return, and pick a time horizon to see the projected future value. Compare different rates and contribution levels to understand how compounding and consistency can grow your money over time.

How long will my investment last?

To estimate how long your money lasts, consider your starting balance, expected annual return, and how much you withdraw each month. A common retirement guideline is the 4% rule — withdrawing about 4% of your portfolio per year has historically helped savings last up to roughly 30 years. Use this investment calculator to model different balances, returns, and withdrawal amounts.

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