CD Rate Calculator
Compare two certificates of deposit side by side and see which one earns more by maturity.
US certificates of deposit are quoted in APY — an effective rate — so enter each CD’s deposit, APY, and term in months to get its maturity value and total interest earned. The calculator then tells you exactly how much more the winning CD pays, making brokered-CD and bank-CD comparisons trivial.
CD A
CD B
How to use this calculator
- Step 1: Fill in CD A — deposit amount, APY as a percentage, and term in months.
- Step 2: Fill in CD B with the competing offer’s deposit, APY, and term.
- Step 3: Hit Calculate to get each CD’s maturity value and interest earned.
- Step 4: Read the comparison line — it names the winner and the exact dollar difference.
The formula
Maturity value = deposit × (1 + APY/100)^years; Interest = maturity value − deposit
Worked example
A $15,000 CD at 5.0% APY for 18 months matures at $16,138.95, earning $1,138.95 in interest (15,000 × 1.05^1.5). Compare that against a 12-month CD at a higher rate to see whether the extra six months of compounding is worth it.
Frequently Asked Questions
How is CD interest calculated?
US CDs are quoted in APY (annual percentage yield), which already includes compounding, so maturity value = deposit × (1 + APY)^years. Most bank CDs compound daily, but because the APY is an effective rate you do not need the compounding schedule — the APY alone determines the payout. That is the math this calculator uses.
What happens if I withdraw a CD early?
Banks charge an early-withdrawal penalty — typically several months of interest, sometimes more on long terms. This calculator shows the full-term result, so if there is any chance you will need the money early, check the penalty in the CD terms and consider a shorter term or a no-penalty CD instead.
Are CDs FDIC insured?
CDs from FDIC-member banks are insured up to $250,000 per depositor, per bank, per ownership category — the same protection as a savings account. Brokered CDs bought through a brokerage carry the issuing bank’s FDIC coverage, but selling one before maturity on the secondary market can mean getting less than you paid.
Should I pick a higher APY or a longer term?
It depends on where rates are headed and when you need the money. A longer term at a slightly higher APY usually wins if you can leave the money alone, but locking in long when rates are rising leaves money on the table. Run both scenarios side by side here — and remember a CD ladder spreads that timing risk.
Do I pay taxes on CD interest?
Yes — CD interest is taxed as ordinary income in the year it is credited, even if you leave it in the CD. Banks send a 1099-INT for interest of $10 or more. Holding CDs inside an IRA or other tax-advantaged account defers or avoids that yearly tax hit.