Do CDs compound daily or monthly?

Most US banks compound CD interest daily on a 365-day basis, then credit it to the account monthly or quarterly. Credit unions more often compound quarterly. The rate sheet or the Truth in Savings disclosure states both the compounding method and the crediting schedule, and Regulation DD requires the bank to disclose them.

How much more does daily compounding actually earn?

On a $25,000 CD at 4.25% for one year, daily compounding pays $22.84 more than annual compounding and $1.89 more than monthly. Over five years the daily-versus-annual gap grows to $135.11. It is real money but it is smaller than the gap between two banks' rates almost every time.

Does compounding frequency change my APY?

It changes the APY implied by a nominal rate, yes. A 4.25% APR compounds to 4.3413% APY daily, 4.3338% monthly and 4.3182% quarterly. If the bank quoted you an APY to begin with, the frequency has already been applied and switching it here will not change your payout.

Is CD interest simple or compound?

Standard CDs compound. The exception is a CD set to pay interest out to a linked account each month — once the interest leaves the CD it stops earning, so the account behaves like simple interest. Savers who want monthly income choose this deliberately; anyone maximising the maturity value should leave interest in the CD.

What is the formula for compound interest on a CD?

A = P(1 + r/n)^(nt). P is the deposit, r the nominal annual rate as a decimal, n the number of compounding periods per year and t the term in years. Subtracting P from A gives the interest earned. Every figure on this page comes from that one expression.

CD Compound Interest Calculator

See what daily, monthly and quarterly compounding are worth.

See what daily, monthly and quarterly compounding are actually worth on the same CD — usually less than the rate difference between two banks.

到期时: US$30,783.67
利息: US$5,783.67

您的存单

存款金额

利率

利率标示为

存期

月

5 年

常见存期

复利频率

到期价值: US$30,783.67
累计利息收入: US$5,783.67
实际年化收益率 APY: 4.25%

US$25,000.00 存入 5 年的存单，利率 4.25% APY，每日复利，到期增长至 US$30,783.67 — 即 US$5,783.67 利息，平均每月 US$96.39。

存期内余额

本金利息

以表格形式查看数据

存期内余额
第	本金	利息	余额
开户时	US$25,000.00	US$0.00	US$25,000.00
1y	US$25,000.00	US$1,062.50	US$26,062.50
2y	US$25,000.00	US$2,170.16	US$27,170.16
3y	US$25,000.00	US$3,324.89	US$28,324.89
4y	US$25,000.00	US$4,528.70	US$29,528.70
5y	US$25,000.00	US$5,783.67	US$30,783.67

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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公式与内容最后审核于 2026年7月21日. 银行利率变动频繁——请直接向你的开户机构确认当前利率。

简短回答

How does compound interest work on a CD?

CD compound interest is calculated with A = P(1 + r/n)^(nt), where n is how many times a year the bank credits interest — 365 for daily, 12 for monthly, 4 for quarterly. Each credit joins the principal and earns interest for the rest of the term, which is why the same nominal rate produces a different maturity value at each frequency. The gap is real but small, and most savers overweight it. A $25,000 CD at 4.25% for one year matures at $26,085.34 compounded daily against $26,062.50 compounded annually — $22.84 apart. Stretch that to five years and the gap widens to $135.11, because the effect is cumulative. What matters far more is which number the bank quoted you. If the 4.25% is an APY it already contains the compounding, and switching the frequency changes nothing about your payout; if it is a nominal APR, the frequency is what turns it into the yield you actually receive.

公式与方法

计算方式

A = P(1 + r/n)^(nt)

Compounding frequency enters only through n. Everything else is the standard CD growth formula.

A: Maturity value after compounding
P: Principal — your opening deposit
r: Nominal annual rate as a decimal (4.25% → 0.0425)
n: Credits per year — daily 365, monthly 12, quarterly 4, annual 1
t: Term in years (60 months → 5)

分步说明

1
Divide the nominal rate by n to get the rate applied at each credit.
2
Add 1. This is the growth factor for a single compounding period.
3
Raise it to the power n × t — the number of credits across the whole term.
4
Multiply by the principal for the maturity value.
5
To isolate the compounding effect, run the same figures at n = 1 and subtract.

使用指南

如何使用本计算器

输入四项参数，结果实时呈现。无需提交，也无需注册。

1
Enter the deposit and the nominal rate
Use the bank's rate sheet. Set the toggle to APR if the figure is a nominal rate — compounding frequency only changes the answer when the input is an APR.
2
Set the term
Compounding is cumulative, so the frequency matters more the longer the term. On anything under a year the difference is usually pennies on a five-figure deposit.
3
Switch the compounding control
Move between daily, monthly and quarterly and watch the maturity value and effective APY update. That movement is the entire value of the frequency.
4
Compare against the rate gap
Note the dollar difference, then compare it to what a 0.10% higher rate at another bank would pay. The rate almost always wins.

示例

实例演算

真实数字，完整推演到底——你可以用自己的数据来核对计算器的结果。

The same $25,000 one-year CD at 4.25% nominal, credited at three different frequencies

Deposit: $25,000
Nominal rate (APR): 4.25%
Term: 12 months

Daily (n = 365): $26,085.34
Monthly (n = 12): $26,083.44
Quarterly (n = 4): $26,079.55
Annually (n = 1): $26,062.50

Daily beats annual by $22.84 on a $25,000 deposit — about 0.09% of the balance. Daily beats monthly by $1.89. A bank offering 4.35% compounded annually pays more than one offering 4.25% compounded daily, which is why the rate is the first thing to compare and the frequency is the second.

The same comparison stretched to a five-year term

Deposit: $25,000
Nominal rate (APR): 4.25%
Term: 60 months

Daily (n = 365): $30,918.77
Annually (n = 1): $30,783.67
Difference: $135.11

Five times the term produces roughly six times the compounding gap, because each year's extra interest compounds again in the years that follow. It is still only 0.44% of the closing balance — meaningful on a long term, rarely decisive.

方法论

精确度与假设条件

每一个计算器都有其假设前提。以下是我们的假设，明确列出，让你清楚知道这些数字涵盖了什么、又没有涵盖什么。

The rate is fixed for the whole term and every credit is retained in the CD rather than paid out.
Daily compounding uses a 365-day year, the convention used by most US banks. A handful use 360, which lowers the result very slightly.
Interest is credited on a regular schedule with no partial first period. Real CDs open mid-month and the first credit is prorated.
Figures are gross of tax. CD interest is taxable in the year it is credited, even if you cannot withdraw it until maturity.

计算惯例遵循 Regulation DD（12 CFR 1030），该法规规定了美国金融机构如何披露存款账户的 APY。受保机构的存款由 FDIC 提供保障，按每位存款人、每家银行、每种所有权类别计算，最高保额 $250,000。

一手来源

这些规则从何而来

本计算器遵循的惯例由监管机构制定，而非由我们自行设定。每一条都链接到发布机构，你可以自己去核对，而不必只听我们说。

细节

关键细节与规则

在开立或续存 CD 之前值得快速浏览的要点。

Compounding frequency and interest payout frequency are different settings. A CD can compound daily but pay out monthly, in which case the paid interest leaves the account and stops compounding — that is a simple-interest CD in practice, and its maturity value is lower.
If the bank quotes an APY, the compounding is already baked in. Regulation DD requires the APY to reflect the institution's own compounding method, which is exactly why the APY exists: it makes two differently-compounded CDs directly comparable.
Continuous compounding, A = Pe^(rt), is the mathematical ceiling. At 4.25% for one year it returns $26,085.40 — six cents above daily on $25,000. There is nothing left for a bank to win by compounding more often than daily.
The compounding gap scales with the balance, not with the rate. On $250,000 rather than $25,000, the five-year daily-versus-annual difference becomes $1,351.05 — the same 0.44%, but now large enough to be worth asking about.
Some credit unions compound quarterly and describe the payout as a dividend rather than interest. The arithmetic is identical; only the terminology and the insuring agency (NCUA instead of FDIC) change.

彼此之间的关联

本计算器适合哪些人

Savers comparing two near-identical offers
When two banks are 0.05% apart, the compounding schedule is the tiebreaker people reach for. Run both here first — the frequency usually moves the answer less than the rate gap does, which settles it quickly.
Anyone handed a nominal rate
Brokered CDs and credit-union share certificates are often quoted as a nominal rate with a stated compounding schedule rather than an APY. This page converts that pair into the maturity value the quote actually implies.
Long-term and retirement savers
On a five- or ten-year CD the compounding effect stops being rounding. If the deposit is large and the term long, the frequency is worth confirming in writing before you sign.

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