Estimate your earnings for a short-term certificate of deposit.
Daily
Monthly
Quarterly
Annually
Expected Balance at Maturity (3 Months)
Interest Earned:
After-Tax Gain:
What is a 3-Month CD?
A 3-month Certificate of Deposit (CD) is a short-term savings vehicle offered by banks and credit unions. When you open a 3-month CD, you agree to leave a specific amount of money (the deposit) in the account for exactly three months. In exchange, the financial institution typically pays you a higher yield than a standard savings account.
How Does a 3-Month CD Work?
The primary mechanic of a 3-month CD is the locked-in Annual Percentage Yield (APY). Unlike a high-yield savings account where the rate can fluctuate daily, a CD locks your rate for the entire 90-day period. This provides protection against falling interest rates but requires you to keep your capital stationary for the duration.
Calculating Your 3-Month Earnings
The math behind a CD depends on compounding frequency. While the yield is quoted as an annual figure (APY), the calculation for a 3-month term essentially captures 1/4 of that annual growth. The formula used by this calculator is:
A = P(1 + r/n)nt
A = Final maturity value
P = Initial deposit
r = APY (as a decimal)
n = Compounding periods per year
t = Time in years (0.25 for 3 months)
Typical Returns for 3-Month CDs
Deposit Amount
APY (%)
3-Month Gain (Est.)
1,000
4.50%
11.25
5,000
5.00%
62.50
10,000
5.25%
131.25
50,000
5.50%
687.50
Why Choose a Short-Term CD?
Investors often choose 3-month CDs when they have a large sum of money needed in the near future—such as a house down payment or upcoming tax bill—and want to earn more than a liquid savings account without taking on market risk. It is a core component of "CD Laddering," where investors stagger maturity dates to ensure regular access to cash while maximizing yields.
function calculateCDReturn() {
var principal = parseFloat(document.getElementById('principal').value);
var apyPercent = parseFloat(document.getElementById('apy').value);
var compounding = parseFloat(document.getElementById('compounding').value);
var taxRate = parseFloat(document.getElementById('taxRate').value) || 0;
if (isNaN(principal) || isNaN(apyPercent) || principal <= 0 || apyPercent < 0) {
alert("Please enter valid positive numbers for deposit and APY.");
return;
}
var r = apyPercent / 100;
var t = 0.25; // 3 months is exactly 0.25 years
// Standard formula for compound interest: A = P(1 + r/n)^(nt)
var finalAmount = principal * Math.pow((1 + (r / compounding)), (compounding * t));
var totalInterest = finalAmount – principal;
// Tax calculation
var taxAmount = totalInterest * (taxRate / 100);
var netInterest = totalInterest – taxAmount;
// Display Results
document.getElementById('totalValue').innerText = finalAmount.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('earnedInterest').innerText = totalInterest.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('afterTaxInterest').innerText = netInterest.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('resultBox').style.display = 'block';
}