CD Calculator
Calculate your Certificate of Deposit maturity value, interest earned, and compare term options.
| Term | Maturity Value | Interest Earned | Effective APY |
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Estimate the maturity value and total interest earned on a Certificate of Deposit, factor in an early withdrawal penalty, and compare returns across common CD terms.
How CD Calculator Works
Maturity value is calculated as deposit × (1 + r/n)^(n×t), where r is the annual percentage yield (APY) as a decimal, n is how many times per year the CD compounds (daily, monthly, quarterly, or annually), and t is the term in years. Interest earned is simply the maturity value minus the original deposit.
The calculator also reports an "effective APY," calculated as (1 + r/n)^n − 1 — this is the true annualized growth rate once compounding frequency is factored in, and it's always slightly higher than the stated rate for anything compounding more often than once a year.
For an early withdrawal, the tool calculates how much interest would have accrued over just the penalty period (e.g. 3 months at the same rate) and subtracts that amount from the maturity value, floored at the original deposit so you never see a result below what you put in. A comparison table then reruns the same maturity formula across common terms (6, 12, 18, 24, 36, and 60 months) so you can see how locking in for longer changes the payout.
See It In Action
Who Uses CD Calculator and Why
- Comparing the maturity payout of CDs from different banks that quote different APYs and compounding frequencies.
- Deciding whether locking money into a 12-month vs a 60-month CD is worth the difference in total interest earned.
- Estimating exactly how much you\'d forfeit by cashing out a CD early instead of waiting for it to mature.
- Checking whether a bank\'s advertised APY already reflects its compounding frequency or if the effective yield is actually higher.
Mistakes to Avoid
- Comparing two CDs by their stated APY alone without checking compounding frequency — the calculator\'s "effective APY" figure is what actually determines your payout, and it can differ slightly from the number printed in a bank\'s ad.
- Forgetting that the early withdrawal penalty is measured in months of interest, not a flat percentage of your deposit — a CD held for years but withdrawn after only a few months can still lose a meaningful chunk of the interest earned so far.
- Assuming a penalty can push your payout below your original deposit — this calculator floors the result at your deposit amount, but not every bank\'s actual policy guarantees that, so check your CD\'s specific terms too.
Tips for Best Results
- Use the term comparison table (6 to 60 months) before committing — if rates are similar across terms, a shorter CD often gives you nearly the same return with far less lock-up risk.
- If there\'s a real chance you\'ll need the cash before maturity, run the early-withdrawal scenario before opening the CD, not after, so the penalty isn\'t a surprise.
Fixing Common Problems
My calculated maturity value doesn\'t match my bank\'s official disclosure. — Double check the compounding frequency your bank actually uses (daily vs monthly vs quarterly) — even a small mismatch there changes the result more than most people expect on longer terms.
Terms Explained
APY (Annual Percentage Yield): The rate a bank advertises that already factors in compounding — this calculator\'s "effective APY" recomputes it based on the compounding frequency you select.
Early withdrawal penalty: A forfeiture of a set number of months\' worth of interest charged for taking money out of a CD before its maturity date.