CD Interest Rate Calculator
Enter your deposit, the rate and the term to see what a certificate of deposit will be worth at maturity and how much interest you'll earn.
A certificate of deposit (CD) pays a fixed rate for a set term. Interest compounds — you earn interest on your interest — so the final value is a bit more than the simple rate suggests.
How CD interest is calculated
The maturity value uses the compound interest formula. If your bank quotes an APY, it already reflects compounding; the calculator also shows the effective APY from the rate and frequency you enter.
Maturity value = Deposit × (1 + rate ÷ n)(n × years)
Interest earned = Maturity value − Deposit
APY = (1 + rate ÷ n)n − 1
Interest earned = Maturity value − Deposit
APY = (1 + rate ÷ n)n − 1
| Term | Meaning |
|---|---|
| Deposit | The principal you put in the CD |
| Rate / APY | The annual percentage the CD pays |
| n | Times per year interest compounds |
Worked example
10,000 at 4.5% for 3 years, compounded monthly:
| Maturity = 10,000 × (1 + 0.045/12)^(12×3) | ≈ 11,442.48 |
| Interest earned | ≈ 1,442.48 |
| Effective APY | ≈ 4.59% |
Frequently asked questions
What's the difference between interest rate and APY?
The interest rate is the base annual rate; APY (annual percentage yield) includes the effect of compounding, so it's slightly higher. If your bank gives you an APY, enter it and choose annual compounding for an exact match.
Does compounding frequency matter?
A little. More frequent compounding (daily vs annually) earns marginally more for the same rate. The difference is small at typical CD rates.
Is CD interest taxable?
In most places, yes — CD interest is generally taxable in the year it's earned. Check the rules where you live.
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Estimates for general information only, before tax and early-withdrawal penalties. Not financial advice.