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.
更新日 検証済みの例：6
$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.
| 月 | 利息 | 残高 | 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 |
Each month counts as 365 ÷ 12 days. Banks count the actual days, which can move daily-compounded interest by a few cents.
Simple interest on the deposit at the APR for the penalty period.
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.
照合元：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 %)
照合元：calculator.net CD calculator default inputs (10,000, 5%, 3 years, annually) and its published result, $11,576.25 and $1,576.25 interest
照合元：Python decimal: 12 × (1.05^(1/12) − 1) = 4.888949 %; one year at 5% APY is 10,500 by definition
照合元：Python decimal: r = 365 × (1.04^(1/365) − 1); penalty 10,000 × r × 3/12; 10,000 × 1.04^0.5 − penalty
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.
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.
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.
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.
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.
精度は入力値と計算方法の前提に依存します。十進演算には有効数字50桁を使いますが、推定、数値計算手法、元データの精度はそれより低い場合があります。表示の丸め処理でこれらの制約がなくなるわけではありません。 独立した出典の解答と照合した計算例：6。 例えば、「Regulation DD example: $1,000 six-month CD, 182 days at 6% compounded daily」は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 %)と照合しています。
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.
計画の参考用です。金融機関、税務当局、市場は独自の丸め方、手数料、規則を適用します。契約などの前に該当機関へ金額を確認してください。
この計算機には、独立した出典の解答を使った計算例が 6 件あります。テストに組み込まれており、ここでも実行できます。
預入額と定期的な積立額の将来価値を、日次や連続複利を含む任意の複利頻度で計算します。
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Calculate an annuity's future value from regular payments, the payout a lump sum buys over N years, or how long it lasts at a set withdrawal.
Calculate what a purchase will cost after inflation, what your money will still buy, and your real return after inflation.
毎月の投資信託積立（SIP）の満期価値を試算します。年ごとの増額や、目標に必要な積立額の計算にも対応します。