What is the difference between CD yield and CD rate?

The rate is the input the bank applies to your balance; the yield is the output you receive once compounding and the term have done their work. On a one-year CD compounding daily, a 4.10% rate produces a 4.185% yield. Regulation DD requires banks to advertise the APY precisely so savers compare yields rather than rates.

What is a good CD yield?

A competitive CD yield tracks short-term Treasury yields, because that is the bank's alternative source of funds. If the best CD you can find pays materially less than a Treasury bill of the same maturity, the bank is not competing for your deposit and it is worth looking elsewhere.

How is CD yield taxed?

As ordinary income, at your full marginal rate, in the year the interest is credited — reported on Form 1099-INT when it exceeds $10. There is no preferential rate as there is for qualified dividends or long-term capital gains, which is why the after-tax yield sits so far below the headline.

Does a higher yield always mean a better CD?

No. A higher yield paired with a longer term means you are locked in longer, and one paired with a harsher early withdrawal penalty means less flexibility if rates rise. Compare the yield first, then read the penalty and the renewal terms before deciding.

CD Yield Calculator

Turn a quoted CD rate into the yield you actually keep.

Turn a quoted CD rate into the yield you actually keep — over the term, annualised, and after tax.

満期時: $53,106.31
利息: $3,106.31

あなたの定期預金

預入金額

金利

金利の表示方法

預入期間

月

1 年 6 月

一般的な期間

複利頻度

満期時の金額: $53,106.31
受取利息の合計: $3,106.31
実効年利回り APY: 4.10%

1 年 6 月の定期預金に $50,000.00、金利 4.10% APY、日次複利で $53,106.31 に増加 — 利息は $3,106.31、月平均 $172.57 です。

期間中の残高

元本利息

数値を表で表示

期間中の残高
か月目	元本	利息	残高
開設時	$50,000.00	$0.00	$50,000.00
4mo	$50,000.00	$674.20	$50,674.20
7mo	$50,000.00	$1,185.81	$51,185.81
11mo	$50,000.00	$1,876.00	$51,876.00
14mo	$50,000.00	$2,399.75	$52,399.75
18mo	$50,000.00	$3,106.31	$53,106.31

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.

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計算式とコンテンツの最終確認日 2026年7月21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

How do you calculate the yield on a CD?

A CD's yield is the interest it pays expressed as a percentage of the deposit, and there are three versions of it that get confused with one another. Total yield over the term is simply interest ÷ principal: a $50,000 CD at 4.10% for 18 months earns $3,171.34, a total yield of 6.343%. Annualised yield — the APY — restates that as a per-year figure so terms of different lengths can be compared, here 4.185%. After-tax yield subtracts what you owe, and for most savers it is the only one that describes reality: at a 24% marginal rate the same CD keeps $2,410.22, an after-tax APY of roughly 3.181%. The reason the distinction matters is that CD interest is taxed as ordinary income at your full marginal rate in the year it is credited, not at the long-term capital gains rate, so the headline yield on a CD is further from the yield you keep than on almost any other saving instrument.

計算式と手法

計算方法

Yield = (A − P) / P

Total yield over the term. Annualising it gives the APY: (A/P)^(1/t) − 1.

A: Maturity value at the end of the term
P: Principal — your opening deposit
t: Term in years, used to annualise
APY: Annualised yield — the per-year rate the term-yield implies
τ: Your marginal tax rate; after-tax yield ≈ APY × (1 − τ)

手順

1
Compute the maturity value A with A = P(1 + r/n)^(nt).
2
Subtract the principal to get the interest the CD paid.
3
Divide by the principal. That is the total yield across the whole term.
4
Raise (A/P) to the power 1/t and subtract 1 to annualise it into an APY.
5
Multiply the APY by (1 − your marginal tax rate) for the after-tax yield.

ガイド

この計算機の使い方

4つの入力だけで、結果はその場で表示されます。送信も会員登録も不要です。

1
Enter your deposit and rate
Type the amount and the rate from the bank's rate sheet, setting the toggle to match whether they quoted an APY or a nominal APR.
2
Set the exact term
Yield is only comparable once it is annualised, and annualising needs the true term. A 13-month promotional CD is not a one-year CD.
3
Read the effective APY
The effective APY tile is the annualised yield. This is the figure to carry across to any other offer, whatever term it runs for.
4
Apply your tax rate
Multiply the APY by one minus your marginal rate. Compare that against a Treasury or municipal alternative, which are taxed differently.

例

計算例

実際の数値を最後まで計算しています。ご自身の数字と照らし合わせて、計算機の結果を確かめられます。

An 18-month CD, shown as term yield, annual yield and after-tax yield

Deposit: $50,000
Rate: 4.10% nominal, compounded daily
Term: 18 months
Marginal tax rate: 24%

Interest earned: $3,171.34
Total yield over the term: 6.343%
Annualised yield (APY): 4.185%
After-tax yield: ≈ 3.181%

The three figures describe the same CD and differ by more than three percentage points. Quoting the 6.343% makes the CD look better than a one-year account paying 4.30%; annualising shows it is slightly worse. Always compare annualised.

Two offers on different terms, made comparable by annualising

Offer A: $50,000, 7-month promo at 4.60% APY
Offer B: $50,000, 18-month at 4.10% nominal

Offer A — interest: $1,329.08
Offer A — annualised yield: 4.600%
Offer B — interest: $3,171.34
Offer B — annualised yield: 4.185%

Offer B pays more than twice the dollars, and is the worse rate. That is the whole reason annualised yield exists. Offer A wins on yield but leaves you re-investing after seven months at whatever rate exists then — the trade-off the annualised figure cannot show you.

算出方法

精度と前提条件

どの計算機にも前提条件があります。当サイトの前提を明記しますので、この数値が何を織り込み、何を織り込んでいないかがはっきり分かります。

The after-tax figure applies a single flat marginal rate to all the interest. Real returns straddle brackets, and state income tax is on top of federal.
Yield is calculated on the opening deposit. If you add to the CD, or if the bank pays interest out rather than compounding it, the yield on your average balance differs.
The rate is fixed and the CD is held to maturity. An early withdrawal penalty can push the realised yield below zero on a short holding period.
No fee is assumed. Maintenance fees on a CD are rare but not extinct, and they come straight off the yield.

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

これらのルールの出どころ

この計算機が従う慣行は、当サイトではなく規制当局が定めたものです。各項目は定めている機関にリンクしていますので、当サイトの説明を信じるのではなく、ご自身で確認いただけます。

詳細

重要なポイントとルール

CDを開設または継続する前に知っておきたい要点をまとめました。

Yield and rate are not synonyms. The rate is what the bank applies; the yield is what you end up with after compounding, term length and — if you count it — tax.
CD interest is taxed as ordinary income in the year it is credited, reported on Form 1099-INT. On a multi-year CD you owe tax annually even though you cannot touch the money until maturity, which is a genuine cash-flow consideration on long terms.
Comparing a CD against a Treasury bill needs the tax treatment included. T-bill interest is exempt from state and local income tax, so in a high-tax state a Treasury yielding slightly less than a CD can keep more.
"High-yield CD" is a marketing phrase with no regulatory definition. It usually signals an online bank with no branch network, which is a real cost advantage — but check the minimum deposit and whether the rate is promotional.
Credit unions call the payout a dividend rather than interest and quote a dividend rate alongside an APY. The APY is calculated the same way and remains the figure to compare.

つながり

この計算機が役立つ方

Savers comparing terms that do not match
A 7-month promo against an 18-month standard cannot be judged on interest earned. Annualise both here and the ranking often flips.
Anyone in a higher tax bracket
At a 32% or 37% marginal rate the after-tax gap between a CD and a municipal bond fund narrows sharply. Knowing your after-tax yield is what makes that comparison honest.
Retirees living on interest
Income planning runs on the yield you keep, not the yield advertised. Work from the after-tax figure and the monthly interest line when you build the budget.

CD計算機のすべて

譲渡性預金（CD）の全体像を、9つの専用ツールでカバーしています。

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