حول 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.
الأسئلة
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 The federal minimum is in Regulation D: money withdrawn within six days of deposit must lose at least seven days' simple interest.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.
ما مدى دقة «CD calculator»؟
تعتمد الدقة على مدخلاتك وافتراضات الطريقة. يستخدم الحساب العشري 50 رقمًا معنويًا، لكن التقديرات والأساليب العددية وبيانات المصدر قد تكون أقل دقة؛ تقريب القيم المعروضة لا يزيل هذه الحدود. أمثلة محلولة جرى التحقق منها بمصادر مستقلة: 6. مثلًا، يجري التحقق من «Regulation DD example: $1,000 six-month CD, 182 days at 6% compounded daily» بالرجوع إلى 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 %).
ما مصدر هذه الطريقة؟
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.