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Compound interest calculator

Enter the starting amount, the annual rate, the compounding frequency and the term. The calculator works out the final amount, interest earned and the effective annual rate.

Result

Final amount

Interest earned
Effective annual rate

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This calculation is for informational purposes only and does not replace advice from a qualified professional. Formulas and rates may not fit your exact situation — double-check the figures before making decisions.

How it is calculated

Compound interest formula: final amount = starting amount × (1 + rate ÷ 100 ÷ n) ^ (n × years), where n is how many times a year it compounds. Interest earned = final amount − starting amount.

The more often it compounds at the same nominal rate, the higher the final amount: interest starts earning interest sooner. Over several years, the gap between yearly and daily compounding is not a rounding error — it's a real, noticeable amount.

Effective annual rate = ((1 + rate ÷ 100 ÷ n) ^ n − 1) × 100% — the nominal yearly rate you'd need without compounding to get the same result. It's the right number for comparing offers with different compounding frequencies.

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