CD Calculator
Project the maturity value of a certificate of deposit from your initial deposit, APY, and term.
Certificate of Deposit Calculator
Balance breakdown
| Month | Interest earned | Balance |
|---|
* Results are theoretical projections based on the figures you entered. Actual statements from a bank can differ
slightly because of day-count conventions, rounding rules, posting dates, and whether interest is credited
monthly or at maturity. The total at maturity here is computed directly from the APY you entered:
balance = deposit × (1 + APY)years.
How to calculate CD interest
A certificate of deposit (CD) is a bank account where you lock in a fixed deposit for a fixed term in exchange for a fixed rate. To project the interest earned on a CD you need three things: the initial deposit, the advertised annual percentage yield (APY), and the term in months or years.
Because banks in the United States are required to publish CD rates as APY — the annual return after compounding — the math is straightforward. Multiply 1 plus the APY (written as a decimal) by itself once for every year of the term, then multiply the result by your deposit. The number you get is the balance at maturity; subtracting your original deposit gives the total interest earned.
Example: $10,000 deposited into a 5-year CD paying 4.50% APY grows to about $12,461 at maturity, for roughly $2,461 of interest.
Whether you think of it as a CD interest calculator, a CD rate calculator, or a CD return calculator, the inputs are the same — deposit, APY, and term — and so is the answer.
Certificate of deposit formula
The standard compound-interest formula is:
A = P × (1 + r / n)n × t
where A is the final balance, P is the deposit, r is the nominal annual interest rate, n is the number of compounding periods per year, and t is the term in years.
When you only have the APY, you can use the simpler equivalent form, because APY already absorbs the effect of compounding over a year:
A = P × (1 + APY)t
This is the formula the CD calculator above uses for the final balance. Because APY already reflects a full year of compounding, the maturity figure depends only on your deposit, APY, and term — not on how often a particular bank credits interest internally.
How CD terms and APY work
CD terms in the U.S. typically range from a few months up to 5 years. Shorter CDs (3, 6, or 9 months) pay less but free your money sooner. Longer CDs (3, 4, or 5 years) usually pay a higher APY in exchange for tying up your funds for longer. The slider above covers the full standard range, so it doubles as a CD term calculator for comparing how 1-year, 3-year, and 5-year options change your payout.
APY differs from APR in an important way: APY includes the effect of compounding, while APR doesn't. That's why two CDs with the same APR but different compounding frequencies will have slightly different APYs — and APY is the number you should compare across banks. If you'd like to convert between the two, see our APR & APY calculator.
A traditional CD is a single-deposit instrument: you fund it once, and you can't add money later. Most banks also charge an early-withdrawal penalty if you cash out before maturity. This calculator assumes you hold the CD to maturity, so penalty math is not included.
How to use the CD calculator
Enter your initial deposit, the APY printed on the bank's rate sheet, and the term. You can drag the slider to jump to common CD lengths or type any value in months or years directly — the calculator uses whatever is in the term field as the source of truth, even if it doesn't snap to a slider tick. The growth chart plots one point per month or per year, matching the unit you pick in the term field.
This free online CD calculator works for CDs from any bank or credit union — use it as a bank CD interest calculator before you open an account, as a CD account calculator while comparing offers, or as a CD payout calculator and CD maturity calculator to see exactly what you'll walk away with at the end of the term. There are no rate tables baked in — the math is driven entirely by the values you type. Always confirm the exact balance and interest schedule with your bank, because they may post interest on different cycles than the model assumes.