CD Calculator
Estimate your certificate of deposit earnings, maturity value & APY
🏦 CD details
Last updated June 2026
Method: Maturity value uses the standard compound-interest formula A = P x (1 + r/m)^(m x t). Because banks advertise CDs by APY under federal Truth in Savings rules, we derive the periodic rate from your APY so the result matches what a bank would actually pay.
Included: Maturity value, total interest earned, effective APY, the implied nominal rate, and a year-by-year balance schedule for any deposit, term and compounding frequency.
Not included: Early-withdrawal penalties, taxes on interest, promotional or bump-up rate changes, and bank-specific rounding. Results are estimates, not a deposit offer.
CD calculator: everything you need to know
Put $10,000 into a 12-month certificate of deposit at a 4.50% APY and you'll have $10,450 at maturity - exactly $450 of interest. Stretch that same deposit and rate to a 5-year CD with interest reinvested and it grows to about $12,462, earning roughly $2,462. A CD calculator lets you see those numbers before you lock your money up, so you can compare terms, rates and compounding methods side by side.
A certificate of deposit is a time deposit: you agree to leave a fixed amount with a bank or credit union for a set term - anywhere from a few months to several years - in exchange for a guaranteed, usually higher, interest rate. In return for that locked-in rate, you generally can't touch the money until the CD matures without paying a penalty.
How CD interest is calculated
CDs earn compound interest, meaning each period's interest is added to the balance and then earns interest itself. The value at maturity is:
A = P × (1 + r ÷ m)m × t where P is your deposit, r is the nominal annual interest rate, m is the number of compounding periods per year (365 for daily, 12 for monthly, 4 for quarterly), and t is the term in years. Because banks advertise the APY rather than the nominal rate, this calculator solves the relationship APY = (1 + r/m)m − 1 for the periodic rate, then grows your deposit period by period - giving the same maturity value a bank would.
APY vs. interest rate
The nominal rate (sometimes called the interest rate or APR) is the headline annual rate before compounding. The APY is the true yearly return once compounding is folded in, so it's always equal to or slightly higher than the nominal rate. For example, a 4.41% nominal rate compounded daily works out to about a 4.50% APY. Federal Truth in Savings rules require banks to quote CDs by APY, which is why APY is the apples-to-apples number to compare offers. Our dedicated APY calculator converts between a nominal rate and APY for any compounding frequency, and the simple interest calculator shows what the same deposit would earn with no compounding at all.
Choosing a CD term and strategy
Longer terms usually pay higher rates, but they tie up your cash for longer. A popular middle ground is a CD ladder: instead of one 5-year CD, you split the money across 1-, 2-, 3-, 4- and 5-year CDs. Each year one CD matures, giving you regular access to cash while still capturing longer-term rates on the rest. The calculator above makes it easy to price each rung of the ladder individually.
Safety and taxes
CDs at FDIC-insured banks and NCUA-insured credit unions are protected up to $250,000 per depositor, per institution, per ownership category, making them one of the lowest-risk ways to earn a fixed return. Keep in mind that CD interest is taxable as ordinary income in the year it's credited - even if you don't withdraw it - and the bank reports it on Form 1099-INT once you earn $10 or more. One way to shelter that interest is to hold the CD inside a tax-advantaged retirement account; an IRA calculator or Roth IRA calculator shows how those accounts change the after-tax picture.
How to use this CD calculator
You only need three numbers from the bank's offer to get an accurate result:
- Deposit amount. Enter how much you plan to put in. CDs are funded once at opening, so this is your full principal.
- APY. Type in the advertised annual percentage yield - the federally required headline number - not the nominal rate. If a bank only shows a nominal rate, it will be slightly lower than the APY.
- Term. Choose how long the money is locked up, from a few months to several years.
Pick a compounding frequency if you want to see the implied nominal rate, then read off the maturity value, total interest and effective APY. Change one input at a time to compare offers: bump the term up a year, or test what a 0.25% higher APY does to your interest.
A worked example: comparing two offers
Say you have $25,000 and two banks are competing for it. Bank A offers a 1-year CD at 4.75% APY; Bank B offers a slightly longer 18-month CD at 4.40% APY. After one year, Bank A pays about $1,188 in interest ($26,188 total). Bank B's lower rate earns less per year, but over its full 18 months the deposit grows to roughly $26,668, about $1,668 of interest. The longer term wins on total dollars, but Bank A frees up your cash six months sooner - which matters if you expect rates to climb and want to reinvest. Plug both into the calculator to see the exact trade-off for your own balance.
Who a CD is right for
A CD fits a specific job rather than being a one-size-fits-all account. It works well when you:
- Have a known timeline - money you won't need until a wedding, tuition payment or home down payment a year or two out.
- Want a guaranteed, fixed return and the discipline of not being able to dip into the funds.
- Worry that rates may fall and want to lock in today's yield before they do.
A CD is a poor fit for your emergency fund or any cash you might need on short notice, because the early-withdrawal penalty can wipe out your interest. For that money, a high-yield savings account or money market account keeps you liquid while still paying interest, and an emergency fund calculator helps you size that cushion first. If you are saving toward a specific number by a target date, the savings goal calculator works out the monthly contribution you need.
Key terms explained
- Principal: the amount you deposit when you open the CD.
- Term: how long you agree to leave the money in, after which the CD matures.
- Maturity: the date the term ends and you can withdraw the principal plus interest penalty-free.
- APY: annual percentage yield - your true one-year return with compounding included.
- Nominal rate: the simple annual rate before compounding; always at or below the APY.
- Compounding frequency: how often interest is added back to the balance (daily, monthly, quarterly or annually).
- Early-withdrawal penalty: the interest you forfeit if you cash out before maturity.
What changes how much your CD earns
Three levers move the final number, and the calculator lets you test each:
- The APY. Even a 0.25% difference adds up on a large balance over a multi-year term, so shopping a few banks is worth the time.
- The term. Longer terms usually carry higher rates and give compounding more time to work, but they tie up your cash longer.
- The deposit size. Interest scales directly with principal; some banks also reserve their best "jumbo" rates for deposits of $100,000 or more.
What does not change your earnings, for a given APY, is the compounding frequency - the APY already accounts for it. Frequency only matters when a bank quotes a nominal rate instead.
Limitations of this estimate
This calculator assumes the money stays untouched until maturity and that the APY is fixed for the whole term. It does not subtract early-withdrawal penalties, federal or state income tax on the interest, or promotional and bump-up rate changes, and it doesn't model the few CDs that pay interest out instead of reinvesting it. Treat the result as a clean, before-tax estimate - your real after-tax, kept-to-maturity return is what counts, and your bank's exact rounding may shift the last dollar or two.
Sources
⚠️ Common mistakes & edge cases
Confusing APY with the nominal rate
If a bank quotes a nominal rate instead of APY, plugging it into a calculator as if it were APY overstates your earnings. Always compare CDs by APY, which is the federally required number that already includes compounding.
Ignoring the early-withdrawal penalty
Breaking a CD before maturity typically costs several months of interest - sometimes more than you've earned. A CD is only the right tool for money you won't need until the term ends; otherwise a high-yield savings account may fit better.
Forgetting taxes on the interest
CD interest is taxed as ordinary income the year it's credited, even on a multi-year CD where you haven't touched the money. Your after-tax return is lower than the headline APY, so budget for the 1099-INT.
Overlooking automatic renewal
Many CDs auto-renew at maturity, often at a lower rate, after a short grace period. If you don't act during that window your cash can roll into a new term you didn't intend - mark the maturity date.
❓ Frequently asked questions
How is CD interest calculated?
A CD grows by compound interest. The value at maturity is A = P x (1 + r/m)^(m x t), where P is your deposit, r is the nominal annual rate, m is how many times per year interest compounds, and t is the term in years. Because banks quote APY (which already includes compounding), this calculator works backward from your APY to find the matching periodic rate, then grows the deposit period by period.
What is the difference between APY and interest rate on a CD?
The interest rate (nominal rate or APR) is the simple annual rate before compounding. APY (annual percentage yield) is what you actually earn in a year once compounding is included, so APY is always equal to or higher than the nominal rate. Federal Truth in Savings rules require banks to advertise CDs by APY, which makes it the right number to compare across banks.
Does compounding frequency change how much I earn?
Slightly. For a fixed APY the ending balance is the same no matter the frequency, because APY already bakes in compounding. The frequency mainly affects the underlying nominal rate: daily compounding needs a lower nominal rate to reach the same APY than annual compounding does. If a bank instead quotes a nominal rate, more frequent compounding produces a higher APY and a larger balance.
What happens if I withdraw from a CD early?
Most CDs charge an early withdrawal penalty, commonly a set number of months of interest (for example 90 days of interest on a 1-year CD or 6-12 months on a long-term CD). The penalty can reduce or even exceed the interest you earned, so this calculator assumes the money stays in the CD until maturity.
Is CD interest taxable?
Yes. Interest earned on a CD is taxable as ordinary income in the year it is credited, even if you do not withdraw it, and the bank reports it on Form 1099-INT when you earn $10 or more. CDs held inside a tax-advantaged account such as an IRA follow that account's tax rules instead.
Is a CD safe?
CDs at FDIC-insured banks and NCUA-insured credit unions are protected up to $250,000 per depositor, per institution, per ownership category. That makes a CD one of the lowest-risk ways to earn a fixed return, though the trade-off is that your money is locked up for the term.
How much does a $10,000 CD earn?
At a 4.50% APY, a $10,000 CD earns about $450 in one year, growing to $10,450. Over 5 years at the same APY (with interest reinvested) it grows to roughly $12,462. Higher APYs and longer terms increase the total, which you can model above.
What is a CD ladder and is it worth it?
A CD ladder splits your money across CDs with staggered maturity dates - for example, equal amounts in 1-, 2-, 3-, 4- and 5-year CDs. As each shorter CD matures you reinvest it into a new long-term CD, so after the ramp-up you always have one CD maturing each year. This gives you regular access to cash and keeps you from locking everything in at a single rate, which is useful when you are unsure whether rates will rise or fall.
Should I pick a CD or a high-yield savings account?
A CD locks in a fixed rate for the whole term, which protects you if rates fall, but your money is tied up and early withdrawal triggers a penalty. A high-yield savings account keeps your money fully accessible and its rate can rise with the market, but it can also drop at any time. Use a CD for money you have a known timeline for (a down payment in 18 months, for instance) and a savings account for your emergency fund.
What happens to my CD at maturity?
When a CD matures the bank gives you a short grace period - often 7 to 10 days - to withdraw the money, move it, or change the term. If you do nothing, most CDs automatically renew into a new term of the same length, frequently at the bank's current (sometimes lower) rate. Mark your maturity date so the renewal is a choice, not an accident.
Can I add more money to a CD after I open it?
Standard CDs are funded once at opening and do not accept additional deposits during the term. If you want to keep adding money, look for an add-on CD, which allows extra deposits, though these are less common and often pay a lower rate. To model a one-time lump sum, just enter your full deposit amount above.
What is a no-penalty CD?
A no-penalty CD lets you withdraw your full balance before maturity without losing interest, usually after an initial holding period of about a week. In exchange, the APY is typically lower than a standard CD of the same term. It can be a middle ground when you want a fixed rate but might need the cash early.
Does CD interest compound, and how often?
Yes. CD interest is added back to the balance so it earns interest itself, which is the essence of compound growth. Banks compound daily, monthly, quarterly or annually. For a stated APY the ending balance is the same regardless of frequency, because APY already reflects compounding - the frequency only changes the underlying nominal rate the bank needs to advertise that APY.
💡 Good to know
Compare by APY, not the nominal rate
Federal Truth in Savings rules require banks to advertise CDs by APY, the number that already includes compounding. Using APY across every offer keeps the comparison apples to apples, so the bank with the higher APY genuinely pays more.
Watch the maturity grace period
When a CD matures you usually get only a 7-to-10-day window to withdraw or change the term before it auto-renews - often at a lower rate. Set a reminder for the maturity date so the next term is your decision.
Your deposit is insured up to $250,000
CDs at FDIC-insured banks and NCUA-insured credit unions are protected up to $250,000 per depositor, per institution, per ownership category - so even if the bank fails, your principal and earned interest are safe within that limit.
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