Effective Interest Rate Calculator

Find the effective annual interest rate for a given nominal rate and compounding frequency.

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Enter a nominal rate and compounding frequency to find the effective interest rate.
%

Your result

8.24%

Effective interest rate

AI explanation

Formula

Effective rate = (1 + nominal rate/n)^n − 1, where n is the number of compounding periods per year

Worked example

8% nominal, compounded quarterly

Worked example: 8% nominal, compounded quarterly
FieldValue
Nominal annual interest rate8
Compounding frequency4
Effective interest rate8.24

Assumptions

  • The effective rate is always equal to or greater than the nominal rate.
  • Informational only.

Frequently asked questions

Why is the effective rate higher than the nominal rate?

Because interest compounds within the year — each compounding period's interest is added to the balance and starts earning interest itself, so the true annual return exceeds the simple nominal rate.

Where is the effective interest rate used?

Banks and lenders often quote a nominal rate, but the effective rate is what actually applies to your balance over a year — useful for comparing deposits or loans that compound at different frequencies.

Does this apply to loans as well as deposits?

Yes — the same math applies whether you're earning interest on a deposit or being charged interest on a loan; a higher compounding frequency increases the effective rate either way.

Related calculators

Sources

This calculator provides a general estimate only and does not constitute financial advice.

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