CD Calculator
A CD calculator estimates how much a certificate of deposit (CD) will be worth at maturity based on your deposit amount, annual percentage yield (APY), term length, and compounding frequency. Banks and credit unions sell CDs as fixed-term, fixed-rate savings products: you lock in a set amount of money for a specific number of months in exchange for a guaranteed rate that usually runs higher than a standard savings account. Enter your starting deposit, the APY your institution quotes, the term in months, and how often interest compounds (monthly, quarterly, or annually), and this calculator projects your ending balance and total interest earned. Because a CD's rate and term are fixed once you open the account, the projection assumes the quoted APY holds steady for the full term with no additional deposits, no withdrawals, and no early closure.
Quick answer
CD growth depends on three inputs you control: your deposit amount, the APY, and the term length.
What this tells you
- •CD growth depends on three inputs you control: your deposit amount, the APY, and the term length.
- •Compounding frequency does not change the ending balance once you have the APY, because an APY already includes compounding. The setting shows the interest rate a bank must credit monthly, quarterly, or annually to deliver the quoted APY.
- •This calculator projects the estimated ending balance and total interest earned at the end of your chosen term.
- •Results assume the APY stays fixed for the entire term with no additional deposits or partial withdrawals.
- •The estimate does not include taxes on interest income, account fees, or early withdrawal penalties.
- •A longer term or a higher APY generally increases projected earnings, but it also locks your funds in for longer.
How to Use
- 1Enter your starting deposit amount, the sum you plan to put into the CD when you open it.
- 2Enter the APY (annual percentage yield) your bank or credit union is quoting for that specific CD product.
- 3Enter the term length in months, for example 12 for a one-year CD or 60 for a five-year CD.
- 4Select how often the bank credits interest (monthly, quarterly, or annually). The projection stays the same, and the calculator reports the equivalent interest rate behind the APY at that frequency. Check the account disclosure if you are not sure which schedule applies.
- 5Select Calculate to view your estimated maturity balance, total interest earned, the term expressed in years, and the equivalent interest rate at your compounding setting.
How It Works
Formula
Ending balance = Deposit x (1 + APY)^t
Equivalent interest rate = n x ((1 + APY)^(1/n) - 1)An APY already includes compounding, so the calculator applies it once per year of the term. Using P for your deposit, r for the decimal APY, and t for the term in years, ending balance equals P x (1 + r) raised to the power of t. A term that is not a whole number of years uses the fraction, so 18 months is t = 1.5. Interest earned is the ending balance minus your deposit. The compounding frequency n does not change that result. It feeds the second line, which converts the APY back into the nominal interest rate a bank must credit n times a year to produce it, the same conversion Regulation DD defines in the other direction. All dollar figures are rounded to the nearest cent.
Calculation note: values are processed in the order shown above, using the current input units.
Worked Examples
$10,000 CD, 4.8% APY, 2-year term, monthly compounding
The APY applies once per year for two years: $10,000 x 1.048^2 = $10,983.04, so $983.04 in interest. Monthly crediting does not raise that figure, because the 4.8% APY already includes it. What monthly changes is the rate behind the yield: the bank credits about 4.698% a year in twelve installments to deliver 4.8% APY, and the calculator reports that as the equivalent interest rate.
$5,000 CD, 5.25% APY, 1-year term, quarterly compounding
One year at 5.25% APY is $5,000 x 1.0525 = $5,262.50, or $262.50 in interest. With quarterly crediting the equivalent interest rate is about 5.150%, which is the number a disclosure lists next to the APY.
$25,000 CD, 4.5% APY, 5-year term, annual compounding
Annual crediting applies the full 4.5% once per year across five years: $25,000 x 1.045^5 = $31,154.55, or $6,154.55 in interest. With annual crediting the interest rate and the APY are the same figure.
$2,000 CD, 3.75% APY, 6-month term, monthly compounding
A six-month term is half a year, so the balance is $2,000 x 1.0375^0.5 = $2,037.15, or $37.15 in interest. The equivalent monthly-credited rate is about 3.687%. A bank that credits interest in whole months can land a cent or two away from this figure.
$50,000 CD, 5.0% APY, 3-year term, quarterly compounding
Three years at 5.0% APY: $50,000 x 1.05^3 = $57,881.25, for $7,881.25 in interest. Quarterly crediting corresponds to an interest rate of about 4.909%.
$1,000 CD, 4.0% APY, 9-month term, monthly compounding
Nine months is 0.75 of a year, so the balance is $1,000 x 1.04^0.75 = $1,029.85, or $29.85 in interest, with an equivalent monthly-credited rate of about 3.928%.
Comparing a 12-month and a 24-month CD for the same $15,000
Luis has $15,000 he will not need for at least two years and two quotes from the same credit union: 4.35% APY on a 12-month share certificate and 4.10% APY on a 24-month one. The 24-month certificate earns $1,255.21 by maturity. The 12-month one earns $652.50 in its first year, and renewing it at the same 4.35% for a second year would reach $16,333.38, which is $78.17 more than the 24-month option. That $78.17 is the price of certainty, because the 24-month rate is locked while the renewal rate in year two is whatever the credit union offers then. Splitting the deposit, $7,500 in each, is a simple two-rung ladder that hedges the bet.
Interest earned on a $10,000 CD by APY and term
Dollar interest at maturity on a $10,000 deposit with the APY applied once per year, which is how APY is defined. For a different deposit, scale the row: $25,000 earns 2.5 times these figures.
| APY | 12 months | 24 months | 36 months | 60 months |
|---|---|---|---|---|
| 3.00% | $300.00 | $609.00 | $927.27 | $1,592.74 |
| 3.25% | $325.00 | $660.56 | $1,007.03 | $1,734.11 |
| 3.50% | $350.00 | $712.25 | $1,087.18 | $1,876.86 |
| 3.75% | $375.00 | $764.06 | $1,167.71 | $2,021.00 |
| 4.00% | $400.00 | $816.00 | $1,248.64 | $2,166.53 |
| 4.25% | $425.00 | $868.06 | $1,329.96 | $2,313.47 |
| 4.50% | $450.00 | $920.25 | $1,411.66 | $2,461.82 |
| 4.75% | $475.00 | $972.56 | $1,493.76 | $2,611.60 |
| 5.00% | $500.00 | $1,025.00 | $1,576.25 | $2,762.82 |
Computed with the formula above. The compounding setting does not change these figures, because an APY already includes compounding. Regulation DD (Truth in Savings, 12 CFR 1030.4(b)) requires banks to disclose the APY on every deposit account and Appendix A to Part 1030 fixes the APY formula, so a 4.00% APY on $10,000 means $400.00 of interest over a one-year term whichever bank quotes it.
APY, early withdrawal penalties, and deposit insurance
APY and APR measure different things. APY is the yield a deposit earns in a year with compounding included, while APR is the yearly cost of a loan stated without compounding (Regulation Z, 12 CFR 1026.22). Regulation DD requires a bank to state a CD's APY in its account disclosure (12 CFR 1030.4(b)), and credit unions follow the NCUA's parallel Truth in Savings rule (12 CFR Part 707). Because the APY already includes compounding, the calculator applies it once per year of the term whatever crediting frequency you select. The frequency setting instead shows the interest rate the bank must credit monthly, quarterly, or annually to deliver that APY, which is the figure a disclosure lists when it shows both a rate and an APY.
A standard CD carries an early withdrawal penalty, and the bank's account agreement sets the size. Federal law fixes only the floor. To count as a time deposit under Regulation D, an account must charge at least seven days of simple interest on any amount withdrawn within six days of the deposit (12 CFR 204.2(c)(1)(i)). Beyond that window the penalty is whatever the agreement says, often a set number of months of interest, and Regulation DD requires the bank to state it in the account disclosure (12 CFR 1030.4(b)(6)). A penalty larger than the interest earned so far comes out of principal, so a CD closed early can return less than you deposited. No-penalty CDs are the exception, with the tradeoff spelled out in their own disclosure.
Deposit insurance covers a CD the same way it covers a savings account. The FDIC insures up to $250,000 per depositor, per insured bank, for each account ownership category (12 U.S.C. 1821(a)(1)(E)), and the NCUA insures credit union shares to the same $250,000 limit (12 U.S.C. 1787(k)). The limit counts principal plus credited interest, so a $250,000 CD is partly uninsured from the first interest posting. Spreading larger balances across ownership categories, such as an individual account and a joint account, or across separately chartered institutions keeps the whole balance covered.
Three limits apply to every projection here. The calculator ignores income tax, and CD interest is ordinary income in the year the bank credits it, reported on Form 1099-INT once it reaches $10 (26 U.S.C. 6049). It assumes you hold to maturity, so no Regulation D or contractual early withdrawal penalty is subtracted. And it treats the quoted APY as fixed for the whole term, which is true for a standard CD but not for a step-up, bump-up, or variable-rate product, and it says nothing about the renewal rate the bank will offer when the term ends.
Common mistakes
- Confusing APY with APR. APY already accounts for compounding, while APR does not, so comparing a CD's APY directly to a loan's APR understates the CD's real return.
- Ignoring early withdrawal penalties. Most CDs charge a penalty, often calculated as a set number of months' interest, if you withdraw before maturity, and that penalty can offset or exceed the interest you have earned so far.
- Assuming the CD renews at the same rate. When a CD matures, many banks automatically renew it into a new CD at whatever rate is current then, which can be lower than your original rate.
- Overlooking the deposit insurance limit. FDIC and NCUA coverage is typically capped at $250,000 per depositor, per institution, per ownership category, so very large deposits may need to be split across institutions.
- Forgetting that CD interest is usually taxable in the year it is credited, even if you do not withdraw the funds before maturity.
- Comparing CDs by headline rate alone. Two CDs with the same quoted APY can produce different real-world outcomes once minimum deposit requirements, interest crediting dates, and penalty terms are factored in.
Limitations
This calculator projects one fixed APY held to maturity with no added deposits, withdrawals, fees, or taxes. Regulation DD defines APY as the yield a deposit earns over a 365-day year with compounding included (Appendix A to 12 CFR Part 1030), so the calculator applies the APY once per year of the term for every compounding setting and uses the setting only for the equivalent interest rate it reports. Terms that are not whole years use the fraction of a year, which can differ by a few cents from a bank that credits interest in whole periods. The projection subtracts no early withdrawal penalty, even though Regulation D requires at least seven days of simple interest on amounts withdrawn within six days of deposit (12 CFR 204.2(c)(1)(i)) and the account agreement sets the penalty after that window. It does not check the FDIC or NCUA $250,000 insurance limit (12 U.S.C. 1821(a)(1)(E)), does not model income tax on the interest, and does not predict the renewal rate offered at maturity. Confirm the APY, compounding method, penalty, and maturity terms in the account disclosure before you open the CD.
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