Finance calculators

CD APY Calculator

Updated Sep 10, 2026 By Infinity Calculator
Rate Formulas Sources

CD Details

Amount placed into the CD at opening.
Nominal (stated) annual rate, before compounding.
Determines the effective APY from your rate.
CD Term
Leave at 0% to see pre-tax figures only.
Effective APY
Derived from your nominal rate & compounding frequency
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Results at Maturity

Total Balance at Maturity
—
Total Interest Earned
—

Step-by-Step Solution

Balance Composition

Breakdown of your maturity balance

Balance Growth Over Time

Principal vs. cumulative interest at each year-end

Accumulation Schedule

Introduction

A CD (certificate of deposit) is a type of savings account where you lock your money away for a set period of time. In return, the bank pays you a fixed interest rate that is usually higher than a regular savings account. The APY, or annual percentage yield, tells you how much your money truly earns in one year after compounding is factored in.

This CD APY calculator helps you find out exactly how much your CD will be worth when it matures. Enter your deposit amount, interest rate, compounding frequency, and term length, and the tool does the rest. It shows your total balance at maturity, the interest you earn, and a full step-by-step breakdown of the math. You can also add your tax rate to see your after-tax earnings.

This calculator gives clear and accurate results, so you can compare CD rates from different banks or see how much interest a CD will pay.

How to Use Our CD APY Calculator

Enter a few details about your certificate of deposit below. The calculator will show your effective APY, total interest earned, and your full balance at maturity.

Initial Deposit: Type the dollar amount you plan to put into the CD. This is the money you give the bank when you open the account.

Annual Interest Rate: Enter the yearly interest rate the bank offers on the CD. This is the stated rate before compounding is applied.

Compounding Frequency: Pick how often the bank adds interest to your balance. Common choices are daily, monthly, or quarterly. More frequent compounding means a slightly higher APY.

CD Term: Enter how long your money will stay in the CD. Use the Years and Months fields to set the exact length. For example, an 18-month CD would be 1 year and 6 months.

Marginal Tax Rate: Enter your combined federal and state tax rate if you want to see after-tax results. CD interest is taxed as regular income. Leave this at 0% if you only want to see pre-tax numbers.

Click Calculate to see your results, step-by-step math, charts, and a full accumulation schedule. Click Reset to clear your entries and start over.

What Is a CD APY Calculator?

A CD APY calculator helps you find out how much money you will earn when you put your savings into a certificate of deposit. A certificate of deposit (CD) is a type of savings account you open at a bank or credit union. You agree to leave your money in the account for a set amount of time, called the term. In return, the bank pays you a fixed interest rate that is usually higher than a regular savings account.

What Does APY Mean?

APY stands for annual percentage yield. It tells you how much your money actually grows in one year after compounding is included.1 Compounding means the bank adds interest to your balance, and then you start earning interest on that interest too. The more often a bank compounds your interest (daily, monthly, or quarterly), the more you earn. APY takes all of that into account, so it gives you a true picture of your earnings.

How a CD Works

When you open a CD, you deposit a lump sum of money. You cannot add more money or withdraw it until the term ends without paying a penalty. CD terms can be as short as one month or as long as ten years. When the term ends, your CD matures, and you get back your original deposit plus all the interest it earned.

APY vs. Interest Rate: What's the Difference?

Banks often show two numbers: the interest rate and the APY. The interest rate is the base rate the bank uses to calculate your earnings. The APY is always equal to or higher than the interest rate because it includes the effect of compounding. When you compare CDs from different banks, always compare APY to APY. That way you see which one truly pays more.

Why Compounding Frequency Matters

A CD that compounds daily will earn slightly more than one that compounds monthly, even if both have the same interest rate. This is because daily compounding adds interest to your balance more often, so your money grows a tiny bit faster. The difference is small on short terms and low balances, but it adds up over time and with larger deposits.

Taxes on CD Interest

Interest earned on a CD is taxable income.2 The IRS treats it as ordinary income, which means you pay your regular income tax rate on it. If you enter your tax rate into this calculator, it will show you how much of your interest you keep after taxes. This helps you understand your real earnings.

Formulas used

Effective APY (Periodic Compounding)
\text{APY} = \left(1 + \frac{r}{n}\right)^{n} - 1
Effective APY (Continuous Compounding)
\text{APY} = e^{r} - 1
Future Value (Periodic Compounding)
FV = P \left(1 + \frac{r}{n}\right)^{n t}
Future Value (Continuous Compounding)
FV = P \cdot e^{r t}
Total Interest Earned
I = FV - P
After-Tax Balance
FV_{\text{net}} = P + I \times (1 - \text{Tax Rate})

Frequently asked questions

What is a good APY for a CD?

A good CD APY depends on the current market. For scale, the FDIC put the national average rate on a 12-month CD at 1.71% in August 2026, and the best offers run well above the average.4 Shorter terms like 6 months may offer slightly different rates than longer terms like 3 or 5 years. Always compare APYs from several banks and credit unions before you choose.

How is APY calculated from a nominal interest rate?

The formula is APY = (1 + r/n)^n − 1, where r is the annual interest rate as a decimal and n is the number of times interest compounds per year. For example, a 5% rate compounded monthly gives APY = (1 + 0.05/12)^12 − 1 = 5.12%. This calculator does this math for you automatically.

What happens if I pick 'Continuously' for compounding?

Continuous compounding means interest is added to your balance at every possible instant. The calculator uses the formula FV = P × e^(r×t), where e is approximately 2.71828. It produces the highest possible APY for a given rate. In practice, most banks compound daily or monthly, but this option lets you see the theoretical maximum.

Can I lose money on a CD?

No, you cannot lose your deposit on a standard CD. Deposits at an FDIC-insured bank are insured to at least $250,000 at each bank.3 However, if you withdraw your money before the term ends, you will usually pay an early withdrawal penalty, which could eat into your interest earnings.

What is an early withdrawal penalty?

An early withdrawal penalty is a fee the bank charges if you take your money out of a CD before it matures. The penalty is often equal to several months of interest, and the bank must disclose it and how it is calculated in the account terms.5 This calculator does not include early withdrawal penalties. Check with your bank for the exact penalty amount on your CD.

How do I use the tax rate field?

Enter your combined federal and state marginal tax rate as a percentage. The calculator will multiply your total interest earned by that rate to show how much goes to taxes. It then displays your after-tax interest and after-tax balance. If you do not want to see tax results, leave the field at 0%.

Is CD interest taxed every year or only at maturity?

In the U.S., CD interest is taxable income, and part of it may have to be reported each year as it accrues, even if no payment is received until maturity.2 Your bank will send you a 1099-INT form each year. This calculator shows the total tax on all interest earned over the full term for simplicity.

Why is my APY higher than the interest rate I entered?

APY includes the effect of compounding. When interest is added to your balance more than once a year, you earn interest on top of previous interest. This makes the effective annual return (APY) slightly higher than the stated nominal rate. The only time they are equal is when compounding happens just once a year.

What happens to my CD when it matures?

When your CD reaches the end of its term, it matures. Most banks give you a short grace period, usually 7 to 10 days, to withdraw your money or renew the CD. If you do nothing, many banks will automatically renew it into a new CD at the current rate, which may be lower or higher than your original rate.

Sources

  1. 12 CFR Part 1030, Appendix A — Annual Percentage Yield Calculation (Regulation DD). Electronic Code of Federal Regulations (eCFR), Consumer Financial Protection Bureau. Part I. Accessed September 10, 2026.
  2. Topic no. 403, Interest received. Internal Revenue Service. Accessed September 10, 2026.
  3. Deposit Insurance. Federal Deposit Insurance Corporation. Accessed September 10, 2026.
  4. National Rates and Rate Caps – August 2026. Federal Deposit Insurance Corporation. 2026;Monthly Rate Cap Information as of August 17, 2026. Accessed September 10, 2026.
  5. 12 CFR 1030.4 — Account disclosures (Regulation DD). Electronic Code of Federal Regulations (eCFR), Consumer Financial Protection Bureau. 1030.4(b)(6)(ii). Accessed September 10, 2026.

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