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CD Calculator

Find what a CD pays at maturity from its APY or its rate and compounding, with interest earned, the APY-to-rate conversion and a month-by-month balance.

CD Calculator: with the default inputs, value at maturity is $10,450.00.

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%
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months
Try an example
Value at maturity
$10,450.00
Interest earned
$450.00
APY
4.5%
Equivalent interest rate (daily compounding)
4.402%
Interest per month (average)
$37.50
Assumptions
  • Interest is left in the CD to compound; no early withdrawal.
  • In APY mode, growth for partial years is (1 + APY)^(months/12), the Regulation DD convention.
  • In rate mode, daily compounding uses 365 periods a year.
Balance over the term
$0$5k$10k036912Month
Balance
Month by month
MonthInterestCumulative interestBalance
1$36.75$36.75$10,036.75
2$36.88$73.63$10,073.63
3$37.02$110.65$10,110.65
4$37.15$147.80$10,147.80
5$37.29$185.10$10,185.10
6$37.43$222.52$10,222.52
7$37.57$260.09$10,260.09
8$37.70$297.79$10,297.79
9$37.84$335.64$10,335.64
10$37.98$373.62$10,373.62
11$38.12$411.74$10,411.74
12$38.26$450.00$10,450.00
Math verified by automated testsUpdated 2026-09-083 sources cited

How this is worked out

The formula

From APY:   A = P × (1 + APY)^(months ÷ 12)
From rate:  A = P × (1 + r/m)^(m × months ÷ 12)
APY = (1 + r/m)^m − 1        (Regulation DD, Appendix A)

P = deposit, r = nominal annual rate, m = compounding periods per year

Open How it’s calculated above to see this worked through with your own numbers.

What you enter

Deposit
A number.in dollars · 0 or more · defaults to 10000
The bank quotes…
US banks must advertise APY, which already includes compounding.APY (annual percentage yield) · Interest rate + compounding
APY
Used when the bank quotes APY.a percentage · from 0 to 100 · defaults to 4.5
Interest rate
The nominal rate, used with the compounding below.a percentage · from 0 to 100 · defaults to 4.4
Compounding
Choose one of 5 options.Daily · Monthly · Quarterly · Semiannually · Annually
Term
A number.from 1 to 600 · whole numbers only · defaults to 12

What you get back

Value at maturitymain answer
Interest earned
APY
Equivalent interest rate (daily compounding)
The nominal rate that produces this APY with daily compounding.
Interest per month (average)

What this assumes

  • Interest is left in the CD to compound; no early withdrawal.
  • In APY mode, growth for partial years is (1 + APY)^(months/12), the Regulation DD convention.
  • In rate mode, daily compounding uses 365 periods a year.

About this calculator

A certificate of deposit pays a fixed rate for a fixed term in exchange for leaving the money alone. Because the rate is locked and the deposit is FDIC-insured up to $250,000, the maturity value is one of the few numbers in personal finance you can compute exactly in advance — which this calculator does, from either figure a bank might quote.

APY vs interest rate

Banks quote two numbers that look alike. The interest rate (sometimes "APR" or "nominal rate") is what's applied each compounding period; the APY is what you actually earn in a year once the compounding is counted. A 4.40% rate compounded daily is a 4.50% APY. US law (Truth in Savings, Regulation DD) requires the APY to be advertised, so it's the number to compare across banks — and if you have it, choose "APY" above and ignore the compounding question entirely. If the disclosure gives only a rate and a compounding frequency, use the second mode and the calculator will derive the APY.

How to use it

Enter the deposit, the quoted APY (or rate and compounding) and the term in months. Solve for answers "what APY do I need to earn $500 on this?" or "how long to reach $11,000?".

Reading the results

  • Value at maturity is what the bank pays out.
  • Interest earned is the gain; in a taxable account it's ordinary income in the year it's credited, even if you don't withdraw it.
  • APY and equivalent rate let you translate between the two ways of quoting.
  • The month-by-month table shows interest accruing; note it grows slightly each month as it compounds.

Things to check before you buy

Early-withdrawal penalties are usually 3–12 months of interest and can eat into principal on a young CD. Many CDs auto-renew at whatever rate applies at maturity, often lower, so diarise the date. If you might need the money, a CD ladder (splitting the deposit across 1-, 2-, 3-, 4- and 5-year terms) keeps some cash maturing every year. And compare against Treasury bills, which are exempt from state income tax and trade freely, before locking in.

Frequently asked questions

What's the difference between a CD's APY and its interest rate?

The interest rate is the nominal figure applied each compounding period; APY is the effective annual return including compounding. APY is always equal to or higher than the rate and is the figure banks must advertise.

How much does a $10,000 CD earn in a year?

At 4.50% APY, exactly $450. At 5% APY, $500. For a 6-month term at 4.50% APY it's about $222, since the APY is scaled to half a year.

Is CD interest taxable?

Yes — as ordinary income in the year it's credited, reported on Form 1099-INT, even for multi-year CDs where you don't receive the cash until maturity. CDs inside an IRA are sheltered.

Are CDs safe?

Deposits at FDIC-insured banks (and NCUA-insured credit unions) are covered up to $250,000 per depositor, per institution, per ownership category. Brokered CDs are covered the same way through the issuing bank.

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