How to use this calculator
A certificate of deposit is a savings product where you leave a lump sum with a bank for a set term in exchange for a fixed rate. The end of the term is called maturity.
- Deposit. Enter the lump sum you will put in at the start.
- APY. Enter the annual percentage yield quoted for the CD. APY already includes the effect of compounding.
- Term in months. Enter the length of the CD, such as 6, 12, 18 or 60.
The results show the value at maturity, the interest earned and the total return % over the whole term.
Worked example
These are the starting values in the calculator above and the results they give. Change any input to see your own numbers.
- Deposit
- $10,000
- APY
- 4.5%
- Term
- 12 months
- Value at maturity
- $10,450
- Interest earned
- $450.00
- Total return
- 4.5%
How CD interest is calculated
APY is the growth of a deposit over exactly one year. For other term lengths, the calculator scales that growth to the term. It converts the months into years, so 18 months is 1.5 years, then raises 1 plus the APY to that power and multiplies by the deposit.
The interest earned is the value at maturity minus the deposit. The total return % is the interest divided by the deposit.
For a 12-month term, the total return equals the APY. For a shorter term it is lower than the APY, and for a longer term it is higher, because the APY is a yearly figure and the total return covers the full term. If you are given a nominal rate instead of an APY, convert it first with the APY calculator.
V = D × (1 + APY)^(m ÷ 12)- V
- value at maturity
- D
- deposit
- APY
- annual percentage yield as a decimal
- m
- term in months
- V − D
- interest earned
- (V − D) ÷ D
- total return
What to check before you compare CDs
- Compare APY with APY. APY puts different compounding schedules on the same footing. A nominal rate and an APY are not directly comparable. The APR vs APY guide explains why.
- Look at total return for the term. A longer CD at a lower APY can still earn more dollars than a shorter CD at a higher APY, simply because it runs longer. Enter both to compare.
- Know the early withdrawal terms. Most fixed-term deposits charge a penalty if you take money out before maturity, often a set number of months of interest. This calculator assumes you hold to the end.
- Check what happens at maturity. Some deposits renew automatically for a new term at whatever rate applies then.
- Think about inflation. If prices rise faster than the APY, the deposit grows in dollars but buys less. The inflation calculator shows the effect.
The result is before any tax on interest and assumes the rate is fixed for the full term with no deposits or withdrawals along the way.
Frequently asked questions
What is a certificate of deposit?
A certificate of deposit, or CD, is a savings product with a fixed term and usually a fixed interest rate. You deposit a lump sum, agree to leave it for the term, and receive your money back with interest at maturity. In return for giving up easy access, the rate is often higher than on an ordinary savings account.
How is interest on a CD calculated?
Interest is added to the balance on a regular schedule, such as daily or monthly, and then earns interest itself. The APY sums up that effect as a single yearly rate. To find the value at maturity, the deposit is grown at the APY for the length of the term, measured in years. The calculator does this from the months you enter.
What happens if I withdraw from a CD early?
Most fixed-term deposits charge an early withdrawal penalty, commonly a set number of months of interest. If you withdraw very early, the penalty can be more than the interest earned so far, which reduces your original deposit. The exact terms vary by provider, so read them before you commit money you might need.
Is APY the same as the interest rate on a CD?
Not quite. The interest rate is the nominal yearly rate before compounding. APY includes compounding, so it is equal to or slightly higher than the interest rate. APY is the better figure to compare, because it shows what you actually earn in a year. This calculator asks for APY for that reason.
Are longer CD terms always better?
Not always. Longer terms often pay a higher rate, but not in every market, and your money is tied up for longer. If rates rise during the term, you are locked into the old rate. Some savers split money across several terms that mature at different times, so part of it becomes available at regular intervals.
This calculator gives estimates for education only. It does not know your full situation and is not financial advice. Reviewed and updated November 15, 2026.