Money & Finance

Compound Interest Calculator

Project how money grows when interest is added to the balance and earns interest over time.

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Compound Interest Calculator

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Savings, Interest & Growth

Compound interest, APY, future value and long-term savings-growth calculations.

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How to use this compound interest calculator

Enter the requested values above and select Calculate. The result updates immediately on the page, so you can change one value and compare different scenarios without leaving the calculator.

Formula and method

Future value = P(1 + r/n)^(nt).

Example

At 7% compounded monthly, $10,000 grows for ten years according to the compound-interest formula.

What this calculator is useful for

Project how money grows when interest is added to the balance and earns interest over time. It is designed for quick estimates and everyday problem solving. When a calculation affects a contract, tax filing, medical decision or other high-stakes situation, verify the result with the appropriate professional or authoritative source.

Compounding works on prior interest too

With $8,000 at a 5% nominal annual rate compounded monthly for six years, use P(1 + 0.05/12)^(12 × 6). The projected balance is about $10,792, before taxes and fees.

What to check: This scenario assumes a constant rate and no added deposits. Nominal rate, APY, and investment return are different concepts; results are mathematical projections, not promised earnings.

Compare with the Savings Growth calculator when that better matches the question you are trying to answer.

Frequently asked questions

What does the Compound Interest Calculator calculate?

Project how money grows when interest is added to the balance and earns interest over time.

How does the calculation work?

Future value = P(1 + r/n)^(nt).

Is this calculator free?

Yes. ERICH Calculators is free to use and no account is required.

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Method, assumptions & corrections

See how formulas, sources and limitations are handled across ERICH Calculators.