CD (Certificate of Deposit) Calculator
Certificate of deposit maturity value and interest.
Details
Maturity value
$10,450.00
After 12 mo at 4.5% APY
This works out what a certificate of deposit is worth at maturity, from the deposit, rate, term and compounding frequency.
It shows the interest earned and the effective APY, which is the figure to compare between banks.
How certificates of deposit work
A certificate of deposit is a savings account with a fixed rate and a fixed term. You agree to leave the money for a set period, and in return the bank pays more than an ordinary savings account.
The trade is access. Withdrawing early triggers a penalty, commonly three to six months of interest on a shorter CD and up to a year on a longer one. That is the whole reason CDs pay more.
Compare banks on APY, not the stated rate. APY includes the compounding, so it is the only number that lets you compare two CDs directly. A 4.5% rate compounded monthly is a 4.594% APY.
The rate is locked for the full term, which protects you if rates fall and costs you if they rise. That certainty is the product.
What to enter
- Deposit amount
- Most CDs have a minimum, often $500 or $1,000. Some banks offer better rates on larger deposits.
- Interest rate and APY
- The rate is what is quoted; the APY is what you compare. Banks are required to disclose APY.
- Term
- Three months to five years typically. Longer terms usually pay more, though not always when short rates are high.
- Compounding frequency
- Daily or monthly for most CDs. It makes a small difference, and APY already accounts for it.
CDs against the alternatives
- CD
- Fixed rate, fixed term, penalty for early access. FDIC insured up to the limit.
- High-yield savings
- Variable rate, no term, full access. Usually slightly lower than a CD, and the rate can fall at any time.
- Treasury bills
- Backed by the US government and exempt from state income tax, which can make them better after tax in a high-tax state.
- Money market account
- Similar to high-yield savings, sometimes with cheque-writing. Variable rate.
- Bonds
- Higher potential return and real risk of loss if sold before maturity. Not a cash equivalent.
What this assumes
The rate is fixed for the term, which is the defining feature of a CD.
Interest is taxable as ordinary income in the year it is credited, even if you do not withdraw it.
How to calculate CD interest
Standard compound interest, with the rate divided by the compounding frequency.
- P
- Deposit
- r
- Annual rate as a decimal
- n
- Compounding periods per year
- t
- Term in years
Convert the rate and divide by the frequency. 4.5% becomes 0.045, then divided by 12 for monthly compounding.
Raise to the total number of periods. Five years compounded monthly is 60 periods.
Multiply by the deposit. $10,000 × (1 + 0.045/12)⁶⁰ = $12,517.96.
Check the APY to compare offers. APY folds compounding into one number, so it is the fair basis for comparing banks.
See a worked example: five years at a locked rate
- Deposit
- $10,000
- Rate
- 4.5%, compounded monthly
- Term
- 5 years
Monthly rate: 0.045 ÷ 12 = 0.00375. Periods: 60.
Value at maturity: $12,517.96.
Interest earned: $2,517.96.
The equivalent APY is 4.594%, which is the figure to quote when comparing against another bank.
$12,517.96 at maturity
Frequently asked questions
You pay a penalty, usually expressed as a number of months of interest. Three to six months on a one-year CD is typical, and up to twelve months on a five-year one.
The penalty can exceed the interest earned if you withdraw very early, which means losing some principal. Check the specific penalty before depositing.
Splitting your money across CDs of different terms, so one matures each year. With $25,000 you might buy five $5,000 CDs at one through five years.
As each matures you reinvest at five years. After the first cycle you have a five-year rate with annual access to a portion, which solves most of the liquidity problem.
It depends on which way rates are heading and whether you need access. A CD locks the rate, which protects you if rates fall and costs you if they rise.
High-yield savings stays flexible and can pay more than a CD when short-term rates are high. For an emergency fund, savings is the right home regardless of the rate.
Yes, within the limits. FDIC insurance covers up to $250,000 per depositor, per insured bank, per ownership category. Credit union CDs are covered equivalently by the NCUA.
The risk that remains is inflation. A CD paying 4.5% while inflation runs at 3% earns a real return of about 1.5%.
Yes, as ordinary income, and in the year it is credited rather than the year you withdraw it. A multi-year CD generates a tax bill each year even though you have not touched the money.
Treasury bills are worth comparing here, since their interest is exempt from state income tax. In a high-tax state that can outweigh a slightly lower headline rate.
A CD you can close early without a penalty, usually after an initial waiting period of about a week.
The rate is lower than a standard CD of the same term, which is the price of the flexibility. It sits between a CD and a savings account in both rate and access.
Problems people actually run into
Putting the emergency fund in a CD
The higher rate is tempting, but an emergency fund has to be available on the day you need it, and that is exactly when the penalty applies.
A ladder or a no-penalty CD is a reasonable compromise. A single long CD holding all your accessible cash is not.
Letting a CD auto-renew
Most CDs renew automatically at maturity, at whatever rate the bank is offering then, which is frequently well below the best available.
There is usually a grace period of about ten days to withdraw or move it. Diary the maturity date when you open the CD, because the reminder letter is easy to miss.
Results are estimates for general information only and are not professional financial, medical, or legal advice. Read our full disclaimer.
Last updated: September 4, 2026