How to use the CD calculator
Enter the amount deposited, the annual percentage yield shown for the CD, and the number of months until maturity. The calculator compounds the APY proportionally across the term.
APY-based CD projection
APY is designed to reflect the effect of compounding over one year. This model uses the stated APY as an effective annual yield and assumes the yield remains unchanged for the term.
Example: Aisha estimates a one-year CD
Aisha deposits $10,000 into a 12-month CD with an illustrative APY of 4.5%. Assuming the interest remains invested, the estimated maturity value is $10,450, including $450 in interest.
For shorter terms, the calculator uses a fractional-year growth factor. The bank may use actual days and its own payout rules, and an early withdrawal can reduce the amount received.
Use the certificate's quoted APY
A $10,000 deposit at 4.5% APY reaches $10,450 after 12 months if the quoted yield applies for the term and interest stays in the account.
For shorter terms, the tool applies the equivalent fraction of annual growth. Early withdrawals, penalties, taxes and changing rates are excluded.
Compare CDs using the same maturity period
A $5,000 CD at a 4% APY reaches $5,200 after one year if interest stays in the account. For six months, the APY-based model uses $5,000 × 1.04^0.5, about $5,099.02, rather than applying a full year of interest.
An early withdrawal can reduce the return, and a CD that pays interest out instead of reinvesting it can follow a different cash-flow pattern. This tool does not subtract withdrawal penalties or taxes.
Assumptions and limitations
What the estimate assumes
Early-withdrawal penalties, taxes, promotional bonuses, callable features, and changing rates are not included.
Sources and reference material
CD Calculator FAQs
What is APY on a CD?
APY is an annualized measure of interest that reflects compounding. It is commonly used to compare deposit yields.
Does this include an early withdrawal penalty?
No. Penalties vary by institution and CD term.
Is CD interest guaranteed?
The calculator assumes the quoted APY and term you enter. Review the institution's actual account agreement for guarantees, conditions, and insurance coverage.
Does the result include taxes?
No.
What is CD maturity value?
Maturity value is the modeled balance at the end of the CD term: the original deposit plus credited interest under the entered assumptions.
Is a higher CD APY always better?
A higher APY increases modeled yield under comparable conditions, but term length, minimum deposits, penalties, liquidity needs, and rate changes available elsewhere can affect the decision.
Estimate only. Review the bank or credit union's actual CD disclosures, rate, APY, early-withdrawal penalty, and deposit-insurance status.