What is the difference between APY and APR on a CD?

APR is the stated annual rate and ignores compounding. APY is the effective annual yield and includes it. A certificate paying 4.5% APR compounded monthly earns 4.593983% over a year; compounded daily the same 4.5% earns 4.602496%. Banks advertise whichever number flatters the product, so the toggle beside the rate field asks which one you typed, and both are printed under the answer. Read the pair, not one of them.

What does the compounding frequency actually change?

Less than the word suggests. $10,000 at 4.5% for five years matures at $12,523.05 compounded daily, $12,517.96 monthly, $12,507.51 quarterly and $12,461.82 annually. The whole distance between compounding every day and once a year is $61.23, and between daily and monthly it is $5.09. The rate and the term move the answer; the frequency mostly moves the marketing.

How much interest does a CD earn each month?

The Interest a month line is the interest earned divided by the months of the term, and the By month rows under the calculator list the interest earned in each month on its own. With interest left in the certificate, every month earns a little more than the one before. A certificate that pays its interest out each month instead earns the deposit times the stated rate divided by 12, every month: set compounding to Monthly and that is the first row of the By month table, $37.50 on $10,000 at 4.5%.

What formula does it use, and how do I do it in a spreadsheet?

Value at maturity is deposit x (1 + r/n)^(n x months/12), where r is the stated annual rate as a decimal and n is 365, 12, 4 or 1 for daily, monthly, quarterly or annual compounding. The yield is APY = (1 + r/n)^n - 1. In Excel or Google Sheets, =10000*(1+0.045/12)^(12*12/12) returns 10459.40, the figure this page opens on, and =EFFECT(0.045,12) returns the 4.593983% yield. When the offer quotes an APY, =NOMINAL(apy,n) gives the stated rate to use.

What happens if I take the money out early?

This page cannot tell you the penalty, because it is a term of your certificate and is not derivable from arithmetic. Banks usually state it as a number of months or days of interest, and it is written on the disclosure you signed. When the disclosure says three months of simple interest, the penalty is the deposit times the rate times 3, divided by 12: $112.50 on $10,000 at 4.5%. To see what you would have earned by then, enter the shorter term in months and read the interest line, then subtract the penalty.

Can it work out a 3 month, 6 month, 5 year or 10 year CD?

Yes. The term field takes any whole number of months from 1 to 600, so a 3 month certificate is 3, a 9 month one is 9, five years is 60 and ten years is 120, and the buttons beside it fill the common ones. A short term earns only its share of the yearly rate: $10,000 at 5% APY for 6 months earns $246.95, not $500. For the calendar date a certificate matures, the date calculator adds months to the day you open it.

Does this calculator know current CD rates?

No, and that is on purpose. Rates differ by bank, by term, by balance tier and by week, so a rate shipped inside a page is wrong somewhere the day after it is written, and a page that quotes one stops being a calculator and starts being an advertisement. Take the rate off the offer in front of you and type it in. The three worked examples under the calculator are illustrations of the arithmetic, not rates anyone is offering. Nothing here is fetched from anywhere and nothing you enter leaves your browser.

How do I compare CD terms, or a ladder?

Switch to Compare terms and the same deposit is run over 3, 6, 12, 24, 36 and 60 months, plus whatever term you have in the field, so the interest each one earns sits in one column. Every row uses the single rate you entered. For a ladder, switch to Ladder: the deposit is split evenly across 2 to 10 certificates that mature a set number of months apart, each rung can carry its own rate from the offer, and the totals sit under the table. $10,000 at 4.5% over five yearly rungs comes to $11,465.58.

Does it work for share certificates, IRA CDs and simple interest CDs?

Yes for the arithmetic. Credit unions call a CD a share certificate and its interest dividends, and the dividend rate and APY go into the same fields. An IRA CD earns the same interest as any other certificate; the account's tax treatment is not modelled here. A certificate that pays simple interest, often one bought through a brokerage, earns the deposit times the rate times the months divided by 12: $750 on $10,000 at 5% for 18 months. The By month table under Monthly compounding shows the monthly payment as its first row.

Is any of this uploaded, and does it need an account?

Neither. The arithmetic runs in the page, there is no account and nothing is sent anywhere. The deposit, rate, term and compounding you last used are remembered in your own browser so the page opens where you left it, and clearing your browser data removes them.

CD Calculator

Enter the deposit, the rate and the term in months, and read what a certificate of deposit is worth the day it matures, with the interest earned, the interest a month, the effective yield and the stated rate beside it. The rate can be entered as an APR or as an advertised APY, compounding runs daily, monthly, quarterly or annually, and the balance is listed by year or month by month. The same money can be laid out over six terms at once, or split into a ladder of certificates with a rate for each rung. There is no rate sheet on this page: the rate in the answer is the one you type, the three worked examples underneath are illustrations rather than offers, and every figure is worked out in your browser.

10,000.00 at 4.5% APR for 1 year, compounded monthly10,459.40Interest 459.40 · effective yield 4.593983% APY

Deposit

Rate (%)

Quoted as

Term (months)

Common terms

Compounding

Value at maturityafter 1 year
10,459.40
Interest earnedon 10,000.00 deposited
459.40
Interest a monththe interest earned divided by 12 months
38.28
APYthe effective annual yield, compounding included
4.593983%
APRthe stated annual rate, compounding excluded
4.5%

Show

Balance along the way

Rows

The balance at the end of each year, and at maturity. Interest is added each month and left in the certificate, which is what makes the yield higher than the rate.

After	Balance	Interest so far
1 year	10,459.40	459.40

Worked examples

Three certificates worked through, each one loadable into the fields above. The figures are illustrations of the arithmetic, not rates on offer.

1 year5,000.00 at 4%, compounded annually
5,200.00 · interest 200.00
1 year 6 months25,000.00 at 5.1%, compounded daily
26,987.41 · interest 1,987.41
2 years2,500.00 at 3.75%, compounded quarterly
2,693.77 · interest 193.77

Common questions

What is the difference between APY and APR on a CD?: APR is the stated annual rate and ignores compounding. APY is the effective annual yield and includes it. A certificate paying 4.5% APR compounded monthly earns 4.593983% over a year; compounded daily the same 4.5% earns 4.602496%. Banks advertise whichever number flatters the product, so the toggle beside the rate field asks which one you typed, and both are printed under the answer. Read the pair, not one of them.
What does the compounding frequency actually change?: Less than the word suggests. $10,000 at 4.5% for five years matures at $12,523.05 compounded daily, $12,517.96 monthly, $12,507.51 quarterly and $12,461.82 annually. The whole distance between compounding every day and once a year is $61.23, and between daily and monthly it is $5.09. The rate and the term move the answer; the frequency mostly moves the marketing.
How much interest does a CD earn each month?: The Interest a month line is the interest earned divided by the months of the term, and the By month rows under the calculator list the interest earned in each month on its own. With interest left in the certificate, every month earns a little more than the one before. A certificate that pays its interest out each month instead earns the deposit times the stated rate divided by 12, every month: set compounding to Monthly and that is the first row of the By month table, $37.50 on $10,000 at 4.5%.
What formula does it use, and how do I do it in a spreadsheet?: Value at maturity is deposit x (1 + r/n)^(n x months/12), where r is the stated annual rate as a decimal and n is 365, 12, 4 or 1 for daily, monthly, quarterly or annual compounding. The yield is APY = (1 + r/n)^n - 1. In Excel or Google Sheets, =10000*(1+0.045/12)^(12*12/12) returns 10459.40, the figure this page opens on, and =EFFECT(0.045,12) returns the 4.593983% yield. When the offer quotes an APY, =NOMINAL(apy,n) gives the stated rate to use.
What happens if I take the money out early?: This page cannot tell you the penalty, because it is a term of your certificate and is not derivable from arithmetic. Banks usually state it as a number of months or days of interest, and it is written on the disclosure you signed. When the disclosure says three months of simple interest, the penalty is the deposit times the rate times 3, divided by 12: $112.50 on $10,000 at 4.5%. To see what you would have earned by then, enter the shorter term in months and read the interest line, then subtract the penalty.
Can it work out a 3 month, 6 month, 5 year or 10 year CD?: Yes. The term field takes any whole number of months from 1 to 600, so a 3 month certificate is 3, a 9 month one is 9, five years is 60 and ten years is 120, and the buttons beside it fill the common ones. A short term earns only its share of the yearly rate: $10,000 at 5% APY for 6 months earns $246.95, not $500. For the calendar date a certificate matures, the date calculator adds months to the day you open it.
Does this calculator know current CD rates?: No, and that is on purpose. Rates differ by bank, by term, by balance tier and by week, so a rate shipped inside a page is wrong somewhere the day after it is written, and a page that quotes one stops being a calculator and starts being an advertisement. Take the rate off the offer in front of you and type it in. The three worked examples under the calculator are illustrations of the arithmetic, not rates anyone is offering. Nothing here is fetched from anywhere and nothing you enter leaves your browser.
How do I compare CD terms, or a ladder?: Switch to Compare terms and the same deposit is run over 3, 6, 12, 24, 36 and 60 months, plus whatever term you have in the field, so the interest each one earns sits in one column. Every row uses the single rate you entered. For a ladder, switch to Ladder: the deposit is split evenly across 2 to 10 certificates that mature a set number of months apart, each rung can carry its own rate from the offer, and the totals sit under the table. $10,000 at 4.5% over five yearly rungs comes to $11,465.58.
Does it work for share certificates, IRA CDs and simple interest CDs?: Yes for the arithmetic. Credit unions call a CD a share certificate and its interest dividends, and the dividend rate and APY go into the same fields. An IRA CD earns the same interest as any other certificate; the account's tax treatment is not modelled here. A certificate that pays simple interest, often one bought through a brokerage, earns the deposit times the rate times the months divided by 12: $750 on $10,000 at 5% for 18 months. The By month table under Monthly compounding shows the monthly payment as its first row.
Is any of this uploaded, and does it need an account?: Neither. The arithmetic runs in the page, there is no account and nothing is sent anywhere. The deposit, rate, term and compounding you last used are remembered in your own browser so the page opens where you left it, and clearing your browser data removes them.

Exact compound interest arithmetic on the deposit, rate, term and compounding you enter. It cannot know your bank's early withdrawal penalty, fees or tax treatment, and it does not carry any rate of its own.