CD calculator: estimate interest and maturity value

Enter an opening deposit, annual percentage yield and CD term to estimate the amount available at maturity. The starting 4% APY is a fictional example, not a current bank offer.

How the estimate works

The model uses opening deposit × (1 + APY ÷ 100)^{months ÷ 12}. APY already includes the effect of compounding for a year, so adding a second compounding adjustment would overstate the result. The model assumes the APY stays fixed and all earnings remain in the account.

For example, a $10,000 deposit at a hypothetical 4% APY grows to $10,400 over twelve months, earning $400 before tax. Over six months, this model estimates $10,198.04. A bank’s actual day count, payment schedule and rounding can produce a slightly different figure.

Check the agreement before opening a CD

Compare the term, opening minimum, APY, interest payment schedule and early-withdrawal conditions. FDIC guidance recommends checking whether a CD can be terminated early and understanding its terms. This estimate does not calculate an early-withdrawal penalty or establish that you can access the money before maturity.

Plan for maturity and renewal

Record the maturity date and review the bank’s renewal notice. The CFPB explains that some CDs renew automatically. Check the renewal rate, new term and any grace period before allowing a renewal; the original rate need not carry forward. Consider whether you will need the cash during the next term.

CD or accessible savings?

If you may need the money for an emergency, compare a CD’s access conditions with a savings account. For several goals, matching different maturities to expected spending dates may be more useful than putting all cash into one term. Check deposit insurance across your eligible balances at the same bank rather than treating each CD as a separate limit.

Sources

• FDIC: Shopping for a certificate of deposit
• CFPB: CD rollover and renewal
• FDIC: Understanding deposit insurance

Sources checked October 11, 2026. This calculator estimates a scenario; it does not recommend a bank or quote a live rate.