CD calculator
What a CD or savings account earns at its APY or rate, with an early withdrawal penalty check.
- ๐บ๐ธ US federal & state rules
- APY formula, Regulation DD Appendix A
- See sources
Balance at maturity
$10,425.00
$425.00 interest over 12 months
- Interest earned
- $425.00
- APY
- 4.25%
- Interest rate (APR, compounded daily)
- 4.162%
- Interest per month on average
- $35.42
This is an example. Enter your numbers above and press the button to see your own result.
Balance over the term
| Month 3 | $10,104.60 |
|---|---|
| Month 6 | $10,210.29 |
| Month 9 | $10,317.09 |
| Month 12 (maturity) | $10,425.00 |
Cashing out early at month 6
| Interest earned so far | $210.29 |
|---|---|
| Penalty (3 months of interest) | -$104.06 |
| You would walk away with | $10,106.23 |
- Interest on a CD or savings account is taxable in the year it is credited, even if you leave it in. Your bank sends Form 1099-INT.
- Early withdrawal penalties vary by bank, from about 90 days to a year or more of interest. Check your account agreement for the exact rule.
Show the math
| Rate from APY | daily compounding: 365 ร ((1 + 4.25%)^(1/365) - 1) = 4.1624% |
|---|---|
| Maturity | $10,000.00 ร (1 + 4.25%)^(12 รท 12) = $10,425.00 |
What to do next
How it works
If you enter the APY, the balance at maturity is deposit ร (1 + APY)^(months รท 12). If you enter the interest rate instead, it is converted to APY with the compounding you choose: (1 + rate รท n)^n - 1.
This follows the APY definition banks use under the Truth in Savings rule (Regulation DD), where APY reflects the interest earned on the principal over a year.
Early withdrawal
Penalties differ by bank, so enter yours as months of interest. The calculator estimates it as simple interest on the deposit for that many months. Some banks charge it on the amount withdrawn or in days, so the exact figure can be a little different.
Sources
Rules applied as of 2026-10-19. See the sources below for details.
- CFPB, Regulation DD Appendix A, annual percentage yieldChecked 2026-10-19
Frequently asked questions
How much will a $10,000 CD earn?
At 4.5% APY for 12 months, $10,000 earns $450 and grows to $10,450. For 18 months at 4% APY it grows to about $10,605.96.
What is the difference between APY and APR?
APY includes compounding, the interest rate (APR) does not. 5% compounded monthly is a 5.116% APY. Banks have to show the APY so accounts can be compared.
How does a CD early withdrawal penalty work?
Most banks charge a set number of days or months of interest. On a $10,000 CD at 5%, a 6-month penalty is about $250, which can be more than you earned if you leave early.
Is CD interest taxed?
Yes, as ordinary income in the year it is credited, even on a multi-year CD you have not cashed. The bank reports it on Form 1099-INT.