Price an 18-month CD against the terms either side.
المعدل معروض كـ
1 سنة 6 ش
المدد الشائعة
دورية احتساب الفائدة المركبة
٢٠٬٠٠٠٫٠٠ US$ في شهادة إيداع لمدة 1 سنة 6 ش بمعدل ٤٫٠٥% APY، بفائدة مركبة يومي، تنمو إلى ٢١٬٢٢٧٫٢٢ US$ — أي ١٬٢٢٧٫٢٢ US$ من الفائدة، بمتوسط ٦٨٫١٨ US$ شهريًا.
الرصيد خلال المدة
| الشهر | أصل المبلغ | الفائدة | الرصيد |
|---|---|---|---|
| عند الفتح | ٢٠٬٠٠٠٫٠٠ US$ | ٠٫٠٠ US$ | ٢٠٬٠٠٠٫٠٠ US$ |
| 4mo | ٢٠٬٠٠٠٫٠٠ US$ | ٢٦٦٫٤٣ US$ | ٢٠٬٢٦٦٫٤٣ US$ |
| 7mo | ٢٠٬٠٠٠٫٠٠ US$ | ٤٦٨٫٥٩ US$ | ٢٠٬٤٦٨٫٥٩ US$ |
| 11mo | ٢٠٬٠٠٠٫٠٠ US$ | ٧٤١٫٢٦ US$ | ٢٠٬٧٤١٫٢٦ US$ |
| 14mo | ٢٠٬٠٠٠٫٠٠ US$ | ٩٤٨٫١٥ US$ | ٢٠٬٩٤٨٫١٥ US$ |
| 18mo | ٢٠٬٠٠٠٫٠٠ US$ | ١٬٢٢٧٫٢٢ US$ | ٢١٬٢٢٧٫٢٢ US$ |
Calculated in your browser using A = P(1 + r/n)nt. Nothing is sent to a server. Figures are before tax; confirm exact terms with your bank.
آخر مراجعة للمعادلات والمحتوى . أسعار البنوك تتغيّر باستمرار — تأكّد من الأسعار الحالية مباشرةً مع مؤسستك المالية.
الإجابة المختصرة
An 18-month CD sits in the gap between the one- and two-year terms, and it exists mainly because banks use odd terms to price promotions without repricing their whole rate sheet. A $20,000 deposit at 4.05% APY earns $1,227.22 over the term and matures at $21,227.22. Because the term is a year and a half, the quoted APY overstates what you get in the first twelve months and understates the total: you receive roughly 6.14% of the deposit across the full period. The comparison worth running is against a 12-month CD followed by a 6-month one. On $20,000, twelve months at 4.25% then six at 4.40% produces $21,303.76 — $76.54 more than the single 18-month term, while giving you a decision point after a year. The 18-month CD wins only when its rate premium is large enough to pay for that lost flexibility, which is exactly what the odd term is designed to test.
المعادلة والطريقة
A = P(1 + r/n)^(nt), t = 1.5
Eighteen months is 1.5 years. Odd terms like 13, 14, 15 and 18 months are handled the same way — set t to months ÷ 12.
Divide the term in months by twelve to get t. Eighteen months is 1.5.
Convert the rate to a decimal and divide by n.
Raise (1 + r/n) to the power n × t.
Multiply by the deposit for the maturity value.
To test the odd term, price a 12-month CD and a 6-month renewal separately and compare.
دليل الاستخدام
Type the amount or drag the slider. Odd-term promotional CDs sometimes attach a minimum well above the bank's standard tier.
The slider takes any number of months, so 13, 14 and 15-month promotional terms can be priced here too — they behave identically.
Odd terms usually exist to carry a promotion. Use the rate quoted for that exact term, and check whether it reverts at renewal.
Price a 12-month CD and then a 6-month one at today's rates. If the split wins, the promotional premium is not paying for the extra lock-up.
أمثلة
المدخلات
النتيجة
6.14% over the term annualises to the 4.05% quoted. Savers comparing an 18-month CD against a 12-month one on total interest alone will always pick the longer term — annualise first, then compare.
المدخلات
النتيجة
On an inverted curve the split wins on both counts — more money and a decision point after a year. The 18-month CD is only the better trade when its rate is above the shorter terms, which is precisely when banks are trying to lengthen their deposit book.
المنهجية
Eighteen months is treated as exactly 1.5 years. Banks count actual days, which shifts the result by a few dollars either way.
The split comparison assumes the 6-month rate is still available in a year. It is the assumption doing all the work, and it is unknowable.
The rate is fixed and interest compounds inside the CD.
Figures are gross of tax. An 18-month CD generates 1099-INT interest in two separate tax years.
تتبع الأعراف المعتمدة هنا قاعدة Regulation DD (12 CFR 1030)، وهي التي تحكم كيفية إفصاح المؤسسات الأمريكية عن APY على حسابات الودائع. والودائع لدى المؤسسات المؤمَّنة محمية من FDIC حتى $250,000 لكل مودع، ولكل بنك، ولكل فئة ملكية.
المصادر الأولية
التفاصيل
Odd terms — 13, 14, 15, 18 months — are a pricing tool. They let a bank run a promotion without moving its published 12- and 24-month rates, so the promotional rate is genuinely competitive but almost never survives renewal.
An 18-month CD straddles two tax years. Interest is taxable in the year it is credited, so you will report part of it before the CD matures and can access the money.
The renewal term is often not 18 months. Many odd-term CDs roll into the nearest standard term — usually 12 or 24 months — at the standard rate. The disclosure states which.
Early withdrawal is typically penalised at 180 days of interest on terms over a year, double the 90 days common on shorter CDs. On $20,000 at 4.05% that is $399.45.
If your horizon is flexible, the odd term is often worth taking. If it is fixed at exactly one or two years, an odd term means either breaking the CD early or leaving money idle after it matures.
كيف ترتبط ببعضها
التطبيقات
If your bank is pushing a 13, 15 or 18-month CD, this page prices whether the premium is real. Compare it against the standard terms either side before accepting.
Eighteen months suits money you will not need for at least a year and probably not for two. The odd term captures a promotional rate for the whole of that window.
An 18-month rung sits neatly between the 12- and 24-month rungs of a ladder, smoothing the reinvestment schedule to every six months rather than every year.
أدوات ذات صلة
الأسئلة الشائعة
At 4.05% APY, a $20,000 deposit earns $1,227.22 and matures at $21,227.22 — a 6.14% return across the full term. The APY is annualised, so the total is roughly one and a half times the annual figure.
الأمان والخصوصية
تستخدم أعراف الفائدة المركبة وAPY نفسها التي تتبعها البنوك بموجب Regulation DD.
لا تسجيل، ولا جدار بريد إلكتروني، ولا اشتراك مدفوع. وكل حاسبة صالحة للاستخدام بالكامل من أول زيارة.
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يُقدَّم الموقع عبر HTTPS دون محتوى مختلط. اقرأ سياسة الخصوصية أو اطّلع على المعادلات والمنهجية التي يقوم عليها كل رقم.
Price your 18-month offer and compare it against splitting the money across two shorter CDs.