CD calculator

Calculate CD interest and maturity value from the APY or APR and compounding, convert APY to APR, and see what an early withdrawal penalty costs.

更新于 已验证的示例:6

$
%
Banks advertise the APY, which includes compounding; the APR is the stated rate before compounding
months of interest
From your deposit agreement; 90 days is about 3 months
months
更多选项
%
Your marginal rate; CD interest is taxed as ordinary income
试一试
Value at maturity
$
Value at maturity: $10,400.00
小数位数:2;取最近值,等距时取偶数末位
Interest earned
$400.00
APY
4.0000%
APR (stated rate)
3.9223%
Early withdrawal penalty
$98.06
Cash-out value after the penalty
$10,099.98
Gain if cashed out early
$99.98
Penalty covered after
3.0months

$10,000.00 at 4% APY (3.9223% APR) grows to $10,400.00 over 12 months, earning $400.00. Cashing out after 6 months returns $10,099.98 once the $98.06 penalty is taken.

Balance and what you would get by cashing out

$10K$10.1K$10.2K$10.3K$10.4K02.557.510MonthsDepositCash out at 6 mo
BalanceCash-out value after penalty

Interest kept: at maturity or cashed out at 6 months

At maturity$400By month 6$198Penalty−$98Kept$100
Month-by-month growth 行数:12
月利息余额Cash-out value after penalty
1$32.74$10,032.74$9,934.68
2$32.84$10,065.58$9,967.52
3$32.95$10,098.53$10,000.48
4$33.06$10,131.59$10,033.54
5$33.17$10,164.76$10,066.71
6$33.28$10,198.04$10,099.98
7$33.39$10,231.42$10,133.37
8$33.50$10,264.92$10,166.86
9$33.60$10,298.52$10,200.47
10$33.71$10,332.24$10,234.18
11$33.83$10,366.06$10,268.01
12$33.94$10,400.00$10,400.00
计算方法 S
  1. APR from the APY

    r=365[(1+0.04)1/365−1]=3.9223%r = 365\left[(1 + 0.04)^{1/365} - 1\right] = 3.9223\%
  2. Term in years

    t=1212=1t = \frac{12}{12} = 1

    Each month counts as 365 ÷ 12 days. Banks count the actual days, which can move daily-compounded interest by a few cents.

  3. Value at maturity

    A=10,000.00×(1+0.04)1=10,400.00A = 10{,}000.00 \times (1 + 0.04)^{1} = 10{,}400.00
  4. Interest earned

    10,400.00−10,000.00=400.0010{,}400.00 - 10{,}000.00 = 400.00
  5. Early withdrawal penalty

    10,000.00×0.03922282044×312=98.0610{,}000.00 \times 0.03922282044 \times \frac{3}{12} = 98.06

    Simple interest on the deposit at the APR for the penalty period.

  6. Cash-out value after 6 months

    10,000.00×(1+0.04)6/12−98.06=10,099.9810{,}000.00 \times (1 + 0.04)^{6/12} - 98.06 = 10{,}099.98
  7. When the penalty is covered

    m=12 ln⁡ ⁣(1+0.03922282044×3/12)ln⁡(1+0.04)=2.99 monthsm = 12\,\frac{\ln\!\left(1 + 0.03922282044 \times 3/12\right)}{\ln(1 + 0.04)} = 2.99\ \text{months}

关于CD calculator

A certificate of deposit pays a fixed rate for a fixed term. The value at maturity is the deposit times (1 + APR ÷ k) raised to k × years, where k is the number of compounding periods a year; entered as an APY, the same value is the deposit times (1 + APY) raised to the years. The calculator converts between the two rates and shows what breaking the CD early leaves you after a penalty of a set number of months of interest.

With the defaults, $10,000 in a 12-month CD at 4.00% APY compounded daily earns $400.00. That APY equals an APR of 3.9223%. Cashing out after 6 months with a 3-month penalty leaves $10,099.98, since the $98.06 penalty takes about half of the $198.04 earned by then.

The penalty is computed as simple interest on the deposit at the APR. Deposit agreements differ, and Regulation DD requires the bank to disclose how its penalty is calculated. Terms in months use 365 ÷ 12 days per month.

计算示例

Regulation DD example: $1,000 six-month CD, 182 days at 6% compounded daily

Deposit
1000
Interest rate
6%
Rate is
年百分率
Compounding
Daily (365)
Term
182
Term in
Days
Early withdrawal penalty
3 months of interest
Cash out early after
3 months
Interest earned
30.37
APY
6.1831%

核验来源:12 CFR 1030 Appendix A, Part I.A, example (2): interest $30.37, APY 6.18% (Python decimal: (1 + 0.06/365)^365 − 1 = 6.183131 %)

$10,000 at 5% compounded yearly for 3 years

Deposit
10,000
Interest rate
5%
Rate is
年百分率
Compounding
Annually
Term
36
Term in
月
Early withdrawal penalty
3 months of interest
Cash out early after
12 months
Value at maturity
11,576.25
Interest earned
1,576.25

核验来源:calculator.net CD calculator default inputs (10,000, 5%, 3 years, annually) and its published result, $11,576.25 and $1,576.25 interest

APY 5% compounded monthly converts to APR

Deposit
10,000
Interest rate
5%
Rate is
APY
Compounding
Monthly
Term
12
Term in
月
Early withdrawal penalty
3 months of interest
Cash out early after
6 months
APR (stated rate)
4.8889%
Value at maturity
10,500.00

核验来源:Python decimal: 12 × (1.05^(1/12) − 1) = 4.888949 %; one year at 5% APY is 10,500 by definition

Defaults: $10,000, 4% APY daily, 12 months, 3-month penalty after 6 months

Deposit
10,000
Interest rate
4%
Rate is
APY
Compounding
Daily (365)
Term
12
Term in
月
Early withdrawal penalty
3 months of interest
Cash out early after
6 months
Interest earned
400.00
APR (stated rate)
3.9223%
Early withdrawal penalty
98.06
Cash-out value after the penalty
10,099.98
Penalty covered after
3.0 months

核验来源:Python decimal: r = 365 × (1.04^(1/365) − 1); penalty 10,000 × r × 3/12; 10,000 × 1.04^0.5 − penalty

常见问题

How is interest on a CD calculated?

Multiply the deposit by (1 + APR ÷ k) to the power k × years, where k is the compounding periods per year, and subtract the deposit. $10,000 at a 5% APR compounded yearly for 3 years grows to 10,000 × 1.05³ = $11,576.25, so the interest is $1,576.25. With the rate given as an APY, use (1 + APY) to the power of the years instead.

What is the difference between APY and APR on a CD?

The APR is the stated yearly rate before compounding; the APY includes compounding and shows what $100 earns in a year. A 5% APY compounded monthly is an APR of 4.8889%, and a 6% APR compounded daily is an APY of 6.1831%. Regulation DD (Truth in Savings) requires banks to disclose both, and the APY is the one to compare CDs on.

What is the penalty for withdrawing a CD early?

Whatever the deposit agreement says, usually a number of months or days of interest. The federal minimum is in Regulation D: money withdrawn within six days of deposit must lose at least seven days' simple interest. On $10,000 at a 3.9223% APR, a 3-month penalty is 10,000 × 0.039223 × 3 ÷ 12 = $98.06.

Can an early withdrawal penalty eat into the principal?

Yes, when the penalty is larger than the interest earned so far. On $10,000 at 4% APY, one month earns $32.74, but a 3-month penalty is $98.06, so cashing out returns $9,934.68 and you lose $65.32 of your deposit. With these terms the penalty is covered after about 3 months.

Are CDs FDIC insured?

Yes. The FDIC lists certificates of deposit among insured deposits, covered up to $250,000 per depositor, per insured bank, for each account ownership category. Coverage is principal plus interest accrued through the date the bank fails, so a $245,000 deposit at 4% APY passes the limit after about 6.2 months.

“CD calculator”有多准确?

准确性取决于输入值和方法的假设。十进制运算使用50位有效数字,但估算、数值方法和源数据的精度可能较低;显示时的舍入并不能消除这些限制。 已按独立来源核验的计算示例:6。 例如,“Regulation DD example: $1,000 six-month CD, 182 days at 6% compounded daily”根据12 CFR 1030 Appendix A, Part I.A, example (2): interest $30.37, APY 6.18% (Python decimal: (1 + 0.06/365)^365 − 1 = 6.183131 %)进行核验。

这种方法出自哪里?

12 CFR 1030 (Regulation DD, Truth in Savings), Appendix A: annual percentage yield calculation; 12 CFR 204.2(c)(1)(i) (Regulation D): minimum early withdrawal penalty on time deposits; 12 CFR 1030.4(b)(6)(ii): disclosure of early withdrawal penalties; FDIC: Understanding deposit insurance.

关于此计算器

A=P(1+rk)kt=P(1+APY)t,APY=(1+rk)k−1,penalty=P r m12A = P\left(1+\tfrac{r}{k}\right)^{kt} = P(1+\text{APY})^{t},\qquad \text{APY} = \left(1+\tfrac{r}{k}\right)^{k}-1,\qquad \text{penalty} = P\,r\,\tfrac{m}{12}

来源

  1. 12 CFR 1030 (Regulation DD, Truth in Savings), Appendix A: annual percentage yield calculation
  2. 12 CFR 204.2(c)(1)(i) (Regulation D): minimum early withdrawal penalty on time deposits
  3. 12 CFR 1030.4(b)(6)(ii): disclosure of early withdrawal penalties
  4. FDIC: Understanding deposit insurance

仅用于规划。贷款机构、税务机关和市场采用各自的舍入方式、费用和规则;作出承诺前,请向相关机构确认数值。

已对照来源验证

此计算器包含 6 个已解示例,答案来自独立来源。这些示例会在测试套件中运行,你也可以在此运行验证。

相关计算器