See what a certificate of deposit is worth at maturity. Enter the opening deposit, the annual rate, how often interest compounds, the term in years and months, and an optional marginal tax rate. You get the end balance, the interest earned, and a month-by-month accumulation schedule.
Check the account terms
This projection assumes the stated rate stays fixed, interest remains in the CD, and there are no fees or early withdrawals. An actual product may credit interest on a different schedule, pay interest out, or charge an early-withdrawal penalty. Compare the issuer's rate, APY, crediting terms, and penalty disclosure before using a result for a decision. The CFPB explains how APY reflects compounding and describes CD withdrawal penalties. The IRS explains when CD interest is included in taxable income, and the FDIC explains deposit-insurance ownership categories.
APY vs. APR at 5% for 3 years on $10,000
| Compound | Equivalent APY | End balance |
|---|---|---|
| Annually (APY) | 5.000% | $11,576.25 |
| Semiannually | 5.063% | $11,596.93 |
| Quarterly | 5.095% | $11,607.55 |
| Monthly (APR) | 5.116% | $11,614.72 |
| Continuously | 5.127% | $11,618.34 |
Examples
$10,000 at 5% APY for 3 years
A $10,000 CD at 5% compounded annually grows to $11,576.25 — $1,576.25 of interest. Year 1 ends at $10,500, year 2 at $11,025, year 3 at $11,576.25.
Same CD taxed at 25%
In the simplified 25% tax scenario, the projected balance is $11,160.92. Gross modeled interest is $1,547.90; the model deducts $386.97, leaving $1,160.92 of interest in the account. Actual tax treatment and timing may differ.
A 6-month CD
The same $10,000 at 5% APY for six months grows to $10,246.95. Short terms are shown month by month rather than as a full year.
$10,000 at 5% APY for 10 years
With one fixed 5% APY for the full term, $10,000 grows to $16,288.95 and earns $6,288.95. The calculator assumes the interest stays in the account. An actual bank may not offer that rate for ten years, and a shorter CD renewed repeatedly would face unknown future renewal rates.
Formula
A CD compounds a single deposit — there are no ongoing contributions. The stated annual rate r is first converted to an effective annual rate at your chosen frequency, then to an equivalent monthly rate so every month of the schedule is consistent:
APY = (1 + r/n)^n − 1 (continuous: e^r − 1)
i = (1 + APY)^(1/12) − 1
The schedule assigns balance × i of interest to each model month. This is a
monthly-equivalent projection, not a claim that a real CD credits interest
monthly. If you enter a tax rate, the model deducts that fraction of each
month's interest and reinvests the rest. It does not calculate your actual tax
bill or payment date. With tax set to zero, a 5% APY ends each full year 5%
higher, even though the table shows monthly growth.