CD Calculator

Maturity Value and How It Is Calculated

A CD earns interest at a fixed rate for a set period. The maturity value is your original deposit plus all interest earned. The formula is the same compound interest calculation used for any savings product: FV = P(1 + r/n)^(nt). Most banks compound CD interest daily or monthly. Take $8,000 deposited into an 18-month CD at an illustrative 4.25% APY. Compounded monthly, your balance at maturity reaches approximately $8,526. That is roughly $526 in interest for locking your money away for a year and a half. The key difference between a CD and a regular savings account is the commitment. You agree to leave the money untouched for the full term. In exchange, the bank typically offers a higher rate than you would get in a standard or high-yield savings account. That trade-off only works if you genuinely will not need the funds before the maturity date.

What Early Withdrawal Actually Costs

Most banks charge an early withdrawal penalty if you break a CD before its maturity date. The penalty is usually expressed in months of interest. A common structure is 90 days of interest for CDs under 12 months and 180 days for longer terms, though every bank sets its own rules. On the $8,000 example at an illustrative 4.25% APY, six months of interest comes to roughly $170. If you withdraw at month 12 six months early you have earned approximately $345 in interest but give back $170, leaving you with a net gain of about $175. You still come out ahead of a zero-interest checking account, but well behind what the full term would have produced. Before opening a CD, check the specific penalty with your bank and compare it against the rate you could earn in a no-penalty alternative. If there is any chance you will need the money early, a no-penalty CD or a high-yield savings account may serve you better.

Penalty structures vary by bank. The estimates here use a common formula, but confirm the exact terms with your institution before opening a CD.