Quarterly Compound Interest Calculator -

Quarterly compounding adds interest four times a year — every three months. It is common on fixed deposits, certificates of deposit and some bonds and business accounts. Enter your amount, rate and time to see how it grows.

Quarterly Compound Interest Calculator

Calculate growth with interest compounded four times a year.

Results are estimates for educational purposes and are not financial advice. Actual returns depend on your provider's terms, fees and taxes.

Quarterly compounding formula

A = P × (1 + r/4)^{4 × t}

P: Amount invested at the start.
r/4: Interest rate per quarter (annual rate ÷ 4).
4 × t: Number of quarters.
A: Amount at maturity.

How to use

Enter the deposit amount.
Enter the annual rate shown on the deposit or certificate.
Enter the term in years or months (a 3-year deposit is 3 years or 36 months).
Press Calculate.

Worked example

A $8,000 fixed deposit pays 6% per year, compounded quarterly, for 4 years.

Quarterly rate: 6% ÷ 4 = 1.5% = 0.015.
Quarters: 4 × 4 = 16.
Growth factor: 1.015¹⁶ = 1.268986.
Maturity amount: 8,000 × 1.268986 = $10,151.88.
Interest: $2,151.88.

The effective annual rate is (1.015)⁴ − 1 = 6.1364%.

Practical uses

Checking the maturity value printed on a fixed deposit or CD receipt.
Comparing a quarterly-compounding deposit with a monthly-compounding savings account — compare the effective annual rates.
Estimating accrued interest on quarterly-compounding business or bond products.

Assumptions and limitations

Interest is credited at the end of every quarter and reinvested (cumulative deposit). If your deposit pays out interest each quarter instead, the interest does not compound — use the Simple Interest Calculator.
Quarters are treated as exactly one quarter of a year.
Withholding tax, early-withdrawal penalties and fees are not deducted.

Frequently asked questions

What is the quarterly interest rate?

For a nominal annual rate, it is the annual rate divided by 4. An 8% annual rate is 2% per quarter.

What if my term is not a whole number of quarters?

The calculator applies the formula with a fractional exponent. A bank may credit interest only on quarter-end dates, so for part quarters your bank’s figure can be slightly lower.

Is quarterly compounding better than annual?

Yes, at the same nominal rate. At 6%, quarterly compounding gives an effective 6.136% versus 6% for annual.