Certificate of Deposit Calculator
| Ladder rung (of $10,000) | Share | What the rung does |
|---|---|---|
| 6-month CD | $2,500 | earliest liquidity, lowest rate |
| 12-month CD | $2,500 | matures as the 6-month rung renews |
| 24-month CD | $2,500 | the rate-capture rung |
| 60-month CD | $2,500 | longest rate lock, biggest penalty if broken |
Use this when a bank quotes you a CD rate: enter the deposit, the APY, and the term, and see exactly what the certificate pays at maturity - the interest, the monthly average, and what the same money would have earned sitting in the big-bank account you are leaving.
A certificate of deposit is a deal with two sides: the bank locks your best rate in town in exchange for locking your money out of your reach. The math is simple - APY is the annual truth, the term sets how long you hold the lock, and the early-withdrawal penalty is the price of changing your mind. The structures around one CD - the ladder, the Treasury bill alternative - are where the real decisions live.
How to use
- Enter the deposit and the APY the bank quoted - APY, not the nominal APR; the calculator compounds it as advertised.
- Pick the term; the maturity value and monthly average update together.
- Read the big-bank comparison, then decide the structure: one lock, a ladder of rungs, or a Treasury bill instead.
Frequently asked questions
How is CD interest calculated?
By compound growth at the APY: maturity = deposit times (1 + APY) raised to the years in the term. A $10,000 CD at 4.00% APY for 12 months pays $400; at 24 months it pays about $816, because the second year earns interest on the first year's interest. APY already includes the compounding effect - which is why you compare CDs on APY, never on nominal rate.
What happens if I withdraw from a CD early?
An early-withdrawal penalty, typically several months of interest - commonly three months for terms under a year, six to twelve for longer ones, set by each bank's disclosure. The penalty can exceed the interest earned if you break the CD early enough, which is why the emergency fund belongs somewhere liquid and only money you can truly park belongs in a CD.
Are CDs worth it compared to a high-yield savings account?
For money with a known deadline, yes: the CD locks the rate for the whole term, while savings rates float down when the Fed cuts. For money you might need tomorrow, no - the liquid account wins on access. The honest comparison is by term: the CD should pay a premium for the lock, and if it does not, the savings account is the better shape.
What is a CD ladder?
Splitting one deposit across several CDs with staggered terms - say quarters in 6, 12, 24 and 60 months - so a rung matures regularly while the long rungs capture the best rates. The ladder converts a single lock into a rolling schedule of liquidity; every maturity is a choice: spend it, or roll it into the longest term and keep the ladder alive.
Are CDs FDIC-insured?
Yes - up to $250,000 per depositor, per bank, per ownership category, which makes the CD the reference point for risk-free yield. Credit union certificates carry the equivalent NCUA insurance. Above the cap, the Treasury bill is the escape hatch: same practical safety, backed directly by the U.S. government, and exempt from state income tax besides.