CD Calculator
$
4.50%
Maturity Value$10,459.40
Interest Earned$459.40
A certificate of deposit locks a lump sum away for a fixed term in exchange for a guaranteed yield, and this calculator shows what that deposit grows to at maturity. You choose the term and how often interest compounds, and it applies the standard compound-interest formula to return both the maturity value and the interest earned. It is built for the single up-front deposit a CD uses, with no ongoing contributions.
Formula
A = P(1 + r/n)^(n·t)
- P
- Initial deposit (principal)
- r
- Annual rate as a decimal (APY ÷ 100)
- n
- Compounding periods per year (1, 2, 4, 12, or 365)
- t
- Term in years (3mo = 0.25, 6mo = 0.5, and so on)
How it works
- Enter your deposit amount and the annual percentage yield (APY) offered on the CD.
- Pick a term from the preset options (3 months, 6 months, 1, 2, 3, or 5 years) and a compounding frequency (annual, semi-annual, quarterly, monthly, or daily).
- The calculator compounds the deposit at the APY for the term length, then reports the maturity value and subtracts the principal to show the interest earned.
Worked example
A $10,000 deposit in a 2-year CD paying 4.5% APY, compounded monthly.
- Monthly factor: 1 + 0.045 / 12 = 1.00375; periods n·t = 12 × 2 = 24.
- Maturity value: 10,000 × 1.00375^24 ≈ $10,939.90.
- Interest earned: 10,939.90 − 10,000 = $939.90.
The CD matures at about $10,939.90, earning roughly $939.90 in interest over two years.
Frequently asked questions
- What is the difference between APY and the interest rate?
- APY already reflects the effect of compounding over a year, while a nominal interest rate does not. This calculator treats the value you enter as the rate and compounds it at your chosen frequency, so for a true apples-to-apples figure enter the rate your bank quotes consistently.
- Can I add monthly contributions to a CD here?
- No. A certificate of deposit is funded by a single up-front deposit and cannot take ongoing contributions, so this calculator grows one lump sum. For recurring deposits use a savings or compound-interest calculator instead.
- Does it account for early-withdrawal penalties or taxes?
- No. The result assumes you hold the CD to maturity and ignores penalties for cashing out early as well as any income tax owed on the interest. Both can reduce your real return.
- How does compounding frequency affect the result?
- More frequent compounding earns slightly more because interest starts earning interest sooner. The gap between monthly and daily compounding is usually small, but at the same rate daily compounding always yields a touch more than annual.