How Does a CD Work? Certificates of Deposit Explained

How certificates of deposit work: fixed rates and terms, early withdrawal penalties, maturity, CD ladders and how CDs compare with high-yield savings.

By Fountain Finances Editorial Team Published Updated 4 min read

Editorial note: This guide is for general education, not individualized financial advice. We independently research every topic and cite our sources. Our editorial standards · How we make money.

Quick answer

A CD (certificate of deposit) is a bank or credit union deposit that pays a fixed rate for a fixed term, such as 6 months or 5 years. You agree not to withdraw the money until the CD matures; withdrawing early usually costs a penalty. CDs are federally insured up to $250,000 per depositor, per institution, per ownership category.

Key takeaways

  • CDs lock in a fixed APY for the full term, protecting you if rates fall.
  • Early withdrawal penalties — often several months of interest — make CDs best for money you won’t need.
  • At maturity there is a short grace period before most CDs renew automatically.
  • A CD ladder spreads money across terms so part of it becomes available regularly.
In this guide
  1. How a CD works, step by step
  2. CD rates: what determines them
  3. Early withdrawal penalties
  4. What happens at maturity
  5. Types of CDs
  6. CDs vs. high-yield savings accounts
  7. Building a CD ladder
  8. Are CDs safe?
  9. Taxes
  10. When a CD makes sense
  11. The bottom line
  12. Frequently asked questions
  13. Sources

Certificates of deposit are one of the oldest and simplest savings products: you deposit money, agree to leave it alone for a set time and receive a guaranteed rate in return. That simplicity makes them a useful tool for specific goals — as long as you understand the trade-offs. Estimate your earnings with our CD calculator.

How a CD works, step by step

  1. Choose a term — commonly 3, 6, 9 or 12 months, or 2, 3, 4 or 5 years.
  2. Deposit your money. Many CDs have a minimum opening deposit; some have none.
  3. Earn a fixed rate. The APY is locked for the entire term.
  4. Leave the money alone until the maturity date.
  5. At maturity, withdraw your money and interest, move it to a new CD, or let it renew.

Interest is usually compounded daily or monthly. You can often choose to have it added to the CD or paid out to another account.

CD rates: what determines them

CD rates generally follow the broader interest rate environment. When market rates are high, banks pay more to attract deposits; when rates fall, new CD rates fall too. Each bank also sets its own rates based on how much funding it needs.

  • Longer terms often — but not always — pay more. When the yield curve is “inverted,” shorter CDs can pay more than longer ones.
  • Online banks and credit unions frequently offer higher rates than large branch banks.
  • Promotional or “special” terms (such as an 11-month CD) can pay more than standard terms.

The FDIC publishes national average rates for common CD terms, which is a useful benchmark.

Early withdrawal penalties

The trade-off for a guaranteed rate is limited access. If you withdraw before maturity, most banks charge a penalty — typically a set number of days’ or months’ worth of interest, and often more for longer terms.

Example: A $10,000 CD at a 4.50% APY with a 90-day interest penalty. The penalty would be roughly $111. If you withdraw after only a month, the penalty can exceed the interest you have earned, reducing your principal.

Always read the penalty terms before opening a CD, and only deposit money you are confident you will not need.

What happens at maturity

Most banks send a notice before your CD matures. After the maturity date, there is usually a grace period — often about 7 to 10 days — to withdraw or change terms without a penalty. If you do nothing, many CDs automatically renew for the same term at whatever rate the bank is paying then, which may be lower. Put the maturity date on your calendar.

Types of CDs

TypeHow it worksConsider if
TraditionalFixed rate and term, early withdrawal penaltyYou are sure you won’t need the money
No-penaltyWithdraw after a short initial period with no penaltyYou want flexibility and can accept a lower rate
Bump-upRequest a rate increase if the bank raises ratesYou expect rates to rise
Add-onMake additional depositsYou want to keep contributing
JumboLarge minimum depositYou have a large sum and the rate is higher
BrokeredBought through a brokerage accountYou want access to many banks’ CDs; can be sold before maturity at market value

CDs vs. high-yield savings accounts

CDHigh-yield savings
RateFixed for the termVariable
AccessPenalty for early withdrawalAnytime
Best forMoney with a known dateEmergency fund, flexible goals
Risk if rates riseYou are locked in at the lower rateYour rate may rise
Risk if rates fallYou keep the higher rateYour rate may fall

Many savers use both: a high-yield savings account for the emergency fund and CDs for money earmarked for a specific future date.

Building a CD ladder

A CD ladder spreads your savings across several CDs with staggered maturities. For example, with $10,000:

CDAmountTerm
1$2,0001 year
2$2,0002 years
3$2,0003 years
4$2,0004 years
5$2,0005 years

Each year, one CD matures. You can use the money or reinvest it in a new 5-year CD. After four years, you have a CD maturing every year while most of your money earns longer-term rates. Ladders balance access with yield and reduce the risk of locking everything in right before rates rise.

Are CDs safe?

CDs at FDIC-member banks are insured up to $250,000 per depositor, per insured bank, for each account ownership category; credit union share certificates have equivalent NCUA coverage. Brokered CDs are also typically FDIC insured at the issuing bank, but their market value can change if you sell before maturity.

Taxes

CD interest is generally taxed as ordinary income in the year it is credited to your account — even if the CD has not matured. Your bank reports it on Form 1099-INT. Holding CDs in a tax-advantaged account such as an IRA can defer or avoid tax on the interest.

When a CD makes sense

  • Saving for a home down payment, tuition or a planned purchase on a known date.
  • Locking in a rate you expect to fall.
  • Keeping money out of easy reach to avoid spending it.
  • Part of a conservative savings plan alongside other accounts.

The bottom line

A CD trades flexibility for a guaranteed rate. Choose a term that matches when you will need the money, understand the early withdrawal penalty and note the maturity date so it does not renew at a lower rate. Compare options on our CD accounts comparison and see more in the banking hub.

Frequently asked questions

Are CDs a good investment?

CDs are a savings tool rather than an investment with growth potential. They offer a guaranteed return and deposit insurance, which makes them useful for money with a set timeline. Over long periods, they may not keep pace with inflation or with diversified investments.

How much does a CD earn?

Multiply the deposit by the APY and the fraction of a year. $10,000 in a 12-month CD at a 4.50% APY earns about $450. Our CD calculator handles any amount and term.

Can I add money to a CD?

Most traditional CDs accept only the opening deposit. Some banks offer add-on CDs that allow additional deposits.

What happens to a CD if the bank fails?

Insured CDs are protected by the FDIC or NCUA up to coverage limits. Depositors typically receive their insured funds, or the deposit is transferred to another insured institution.

Sources

  1. Deposit Insurance — Federal Deposit Insurance Corporation
  2. National Rates and Rate Caps — Federal Deposit Insurance Corporation
  3. Certificates of Deposit (CDs) — U.S. Securities and Exchange Commission — Investor.gov
  4. Topic No. 403, Interest Received — Internal Revenue Service

This guide is part of our Banking & Savings hub and our complete personal finance guide. Spot an error? Request a correction.

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