See what six months in a CD actually earns.
金利の表示方法
6 か月
一般的な期間
複利頻度
6 か月 の定期預金に $25,000.00、金利 4.40% APY、日次複利で $25,544.08 に増加 — 利息は $544.08、月平均 $90.68 です。
期間中の残高
| か月目 | 元本 | 利息 | 残高 |
|---|---|---|---|
| 開設時 | $25,000.00 | $0.00 | $25,000.00 |
| 1mo | $25,000.00 | $89.87 | $25,089.87 |
| 2mo | $25,000.00 | $180.06 | $25,180.06 |
| 4mo | $25,000.00 | $361.42 | $25,361.42 |
| 5mo | $25,000.00 | $452.58 | $25,452.58 |
| 6mo | $25,000.00 | $544.08 | $25,544.08 |
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.
計算式とコンテンツの最終確認日 . 銀行の金利は頻繁に変動します。最新の金利は必ずご利用の金融機関に直接ご確認ください。
結論から
A 6-month CD locks your deposit for half a year at a fixed rate, and at most banks it is the best-priced short term on the sheet — banks compete hardest here because six months is where deposit money is most mobile. At 4.40% APY a $10,000 deposit earns $217.63 and matures at $10,217.63; $25,000 earns $544.08. The half-year term means you receive roughly half the advertised APY: 4.40% APY over six months is about 2.18% of your deposit, not 4.40%. The interesting comparison is not against savings but against the one-year CD. Rolling a 6-month CD twice at 4.40% produces $26,100.00 on $25,000, against $26,062.50 for a single 12-month CD at 4.25% — the shorter term wins by $37.50, provided the rate is still there in six months. That proviso is the entire decision.
計算式と手法
A = P(1 + r/n)^(nt), t = 0.5
Half a year of compounding. At 4.40% APY that returns about 2.18% of the deposit, not 4.40%.
Convert the 6-month rate to a decimal and divide by n.
Raise (1 + r/n) to the power n × 0.5 — about 182 daily credits.
Multiply by the deposit for the six-month maturity value.
Subtract the deposit to isolate the interest.
To test rolling, square the six-month growth factor and compare it against a 12-month CD.
ガイド
Type the amount or drag the slider. Six-month promotional CDs sometimes require a higher minimum than the standard tier — check before you assume the rate applies.
Banks price each term separately and the six-month line is often the most competitive. Do not carry over the rate from a different term.
You receive roughly half the annualised APY over six months. The interest tile shows the actual dollars rather than the annualised percentage.
Switch the term chip to 12 and compare. If the six-month rate is higher, you are being paid to stay flexible — but only until it renews.
例
入力値
結果
The 4.40% APY delivers 2.18% across six months. Savers routinely expect the full 4.40% and are disappointed at maturity — the APY is a per-year figure and the term is half a year.
入力値
結果
Rolling wins by $37.50 only if the second six-month rate matches the first. If it renews 0.50% lower you finish at $26,037.43 — behind the 12-month CD. The 12-month term is buying rate certainty, and $37.50 is what that certainty costs.
算出方法
Six months is treated as 0.5 years. Banks count actual days, so a 181- or 184-day half-year differs marginally from the figure shown.
The rolling comparison holds the second-term rate constant, which is the assumption most likely to be wrong. It is shown to make the trade-off visible, not as a forecast.
The rate is fixed and the interest compounds inside the CD rather than being paid out.
The savings comparison assumes the savings rate persists. It is variable and can be reduced without notice.
計算の慣行は、米国の金融機関が預金口座のAPYを開示する方法を定めたRegulation DD（12 CFR 1030）に従っています。付保対象の金融機関への預金は、預金者ごと・銀行ごと・所有区分ごとに$250,000までFDICで保護されます。
一次情報
詳細
Six months is where promotional pricing concentrates. If one term on a bank's sheet is materially above the others, it is frequently this one — and it usually reverts to a standard rate on renewal.
A 90-day interest penalty on a six-month CD costs roughly half the term's interest. On $25,000 at 4.40% that is about $271 against $544 earned, so an early withdrawal at the halfway point still leaves you ahead of zero — unlike a 3-month CD.
The APY is annualised regardless of term length. Regulation DD requires it, which is what makes a six-month CD comparable with a five-year one, but it is also why the interest looks smaller than savers expect.
A six-month CD renews twice a year, so you face the reinvestment decision twice as often as on a one-year term. On an inverted curve that is an advantage; when rates are falling it is the main risk.
Pairing a six-month CD with a longer one is the simplest form of laddering — half the money stays liquid within six months, half captures the longer rate.
つながり
活用シーン
Six months is the shortest term that reliably carries a competitive rate. It is the default answer for money you will not need immediately but do not want to commit for a year.
If you think rates are near a peak, six months lets you capture today's rate and reassess before the year is out. If you think they are near a floor, the twelve-month term is the safer choice.
Half a year is long enough to be worth doing and short enough that a mistake is cheap. Most people's first CD should probably be this one.
関連ツール
At 4.40% APY, $217.63 — maturing at $10,217.63. The APY is an annual figure, so a six-month term returns about half of it: 2.18% of the deposit rather than 4.40%.
セキュリティとプライバシー
Regulation DDのもとで銀行が用いるのと同じ、複利とAPYの慣行を使用しています。
登録もメールアドレスの入力も課金もありません。すべての計算機を、初回から制限なくお使いいただけます。
すべての計算はJavaScriptによりブラウザ内で実行されます。サーバーへの送信も保存も行いません。
HTTPSで配信しており、混在コンテンツはありません。詳しくは プライバシーポリシー をご覧ください。すべての数値の根拠となる 計算式と算出方法 も公開しています。
Enter your deposit and the rate your bank quotes, and compare it against a twelve-month lock.