CD Calculator
This CD calculator shows what a certificate of deposit is worth at maturity from three inputs — your deposit, the APY, and the term — along with the total interest earned and what that works out to per month of the lock-up.
Free tool · No sign-up · Using it has no impact on your credit score
The CD's advertised annual percentage yield — fixed for the whole term.
Value at maturity
$10,450
When the CD matures in 1 year, the bank hands back $10,450.
Total interest earned
$450
$450 of guaranteed interest on your $10,000 deposit — the rate is locked, so this number can't shrink.
Average interest per month
$37.50
What the CD earns per month on average — $37.50 for every month the money stays locked.
CD value over the term
What this calculator tells you
A certificate of deposit is the simplest deal in banking: you agree not to touch a lump sum for a fixed term, and the bank pays a fixed APY for the privilege. This calculator turns that deal into concrete numbers — the check you'll receive at maturity, the total interest earned, and the average monthly earnings, which makes it easy to weigh the lock-up against what a liquid savings account would pay.
Because a CD's rate is contractual, these aren't projections in the usual sense — barring an early withdrawal, the maturity value is what you will actually receive, to the penny the bank computes. That certainty is the product. The open question the calculator helps you answer is whether the certainty is worth it: how much interest you're being paid to give up access, and for how long.
How it works
The calculator grows your deposit at the CD's APY for the term's length, measured in years — an 18-month term is 1.5 years of growth. Interest earned is the maturity value minus the original deposit, and the per-month figure divides that interest evenly across the term so different term lengths compare fairly.
APY already includes the effect of however often the bank compounds internally, so no compounding-frequency input is needed — two CDs with the same APY and term pay the same dollars.
Formula and assumptions
Maturity value = deposit × (1 + APY)^(term in months ÷ 12). For the default example: $10,000 × 1.045^1 = $10,450 after 12 months, or $37.50 of interest per month of the lock. The APY is treated as the effective annual rate — which is exactly what banks are required to advertise — so the formula reproduces the bank's own maturity math.
Assumptions: the deposit stays untouched to maturity (an early withdrawal triggers a penalty this calculator doesn't model), interest stays in the CD and compounds rather than being paid out to another account, and the result is pre-tax — CD interest is taxed as ordinary income in the year it's credited, even though you can't spend it until maturity.
Example scenario
A $10,000 deposit in a 12-month CD at 4.5% APY plays out like this:
- Value at maturity
- $10,450
- Total interest earned
- $450
- Average interest per month
- $37.50
Is my result good or bad?
Judge a CD rate against two benchmarks: the best nationally available CDs for the same term, and liquid high-yield savings accounts, both recently in the 4–4.5% APY range. A CD paying meaningfully below a no-strings savings account is a bad deal outright — you'd be accepting a lock-up for less money. Big branch banks routinely offer standard CDs under 1% while online banks pay 4%+ for the identical FDIC-insured product, so shopping beyond your current bank is usually worth several hundred dollars per $10,000.
The term deserves as much scrutiny as the rate. A good result is a maturity date that lands just before you actually need the money — a 12-month CD for a down payment due in 13 months is excellent; a 60-month CD funded with money you might need in year two is a penalty waiting to happen. When the timing is uncertain, a ladder of staggered shorter CDs, or simply a high-yield savings account at a similar rate, buys flexibility for very little yield.
Frequently asked questions
How is CD interest calculated?
From the APY, which by regulation already includes compounding: maturity value = deposit × (1 + APY) raised to the term in years. A $10,000 CD at 4.5% APY pays $450 after 12 months, about $223 after 6 months, and roughly $2,462 after 5 years. Because the rate is fixed at purchase, the payout is contractually guaranteed rather than an estimate.
What happens when my CD matures?
The bank gives you a grace period — typically 7 to 10 days — to withdraw the money, add to it, or move it to a different term. If you do nothing, most CDs automatically renew for the same term at whatever rate the bank currently offers, which is often far below the competitive rate you originally shopped for. Put the maturity date on your calendar; auto-renewal at a stale rate is the most common way CD holders lose yield.
What's the penalty for early withdrawal?
Usually a slice of interest rather than a flat fee — commonly around 3 months of interest on terms up to a year and 6 to 12 months of interest on longer terms, with exact rules in your CD's disclosure. If you haven't yet earned that much, the penalty can eat into your principal at some banks. That's why money with an uncertain timeline belongs in a high-yield savings account instead, even at a slightly lower rate.
What is a CD ladder?
A way to get long-term rates without a long lock: split your money across staggered terms — say five equal pieces in 12-, 24-, 36-, 48-, and 60-month CDs — and as each one matures, roll it into a new 5-year CD. After the first cycle, a rung matures every year, giving you annual access to part of the money while the whole portfolio earns 5-year rates. It also smooths rate risk, since you're never locking everything at one moment's rate.
CD vs high-yield savings — which pays more?
Recently they've paid similar headline rates, so the real trade is rate certainty versus access. A CD locks today's APY for the whole term — valuable if rates fall, costly if they rise — while a savings APY floats with the market and the money stays reachable. Rule of thumb: money with a known spend date goes in a CD maturing just before it; money with an uncertain date stays liquid in savings.
Are CDs FDIC insured?
Yes — CDs at FDIC-member banks are insured up to $250,000 per depositor, per bank, per ownership category, and credit union CDs carry equivalent NCUA coverage. That makes an insured CD's maturity value effectively risk-free. For deposits above the limit, spreading money across multiple banks (or ownership categories, like a joint account) keeps every dollar inside coverage.
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Estimates only. Results assume the inputs you provide and standard fixed-rate math. Actual lender offers, rates, and terms are determined by lending partners based on your credit profile and state. BankMinistry is not a lender. Not financial advice.