Certificate of Deposit (CD) Earning Calculator
Determine exactly how much interest your CD will generate over time.
How to Calculate Certificate of Deposit Rates and Returns
A Certificate of Deposit (CD) is a low-risk savings tool offered by banks and credit unions. Unlike a standard savings account, a CD requires you to leave your money untouched for a fixed period—the term—in exchange for a higher interest rate.
The Mathematics of CD Compounding
To calculate the future value of a CD, we use the compound interest formula:
A = P (1 + r/n)^(nt)
- A: The final amount of money in the account.
- P: The initial principal (your deposit).
- r: The annual interest rate (as a decimal).
- n: The number of times interest is compounded per year.
- t: The time the money is invested for (in years).
Interest Rate vs. APY
When comparing CDs, you will often see two numbers: the Interest Rate and the Annual Percentage Yield (APY). The interest rate is the "base" rate, while the APY reflects the total amount of interest you earn in a year, accounting for the effect of compounding. If interest compounds daily, the APY will be higher than the base interest rate.
Example Calculation
Suppose you deposit $10,000 into a 24-month CD with a 5% interest rate compounded monthly.
- Convert rate to decimal: 0.05
- Compounding periods (n): 12 (monthly)
- Years (t): 2
- Calculation: 10,000 * (1 + 0.05/12)^(12*2) = $11,049.41
- Total Interest: $1,049.41
Why Compounding Frequency Matters
The more frequently your interest compounds, the faster your balance grows. Daily compounding is generally better for the consumer than monthly or annual compounding, as you start earning interest on your interest sooner.