What determines how much a CD pays

A CD earns interest based on three things: the annual percentage yield (APY) the bank offers, how much money you deposit, and how long you lock it away. The bank sets the APY—it varies by institution and changes daily. Your deposit amount and term length are up to you. A $5,000 CD earning 4.50% APY for one year will earn roughly $225 in interest, while the same amount at 3.75% APY earns roughly $188. The difference comes entirely from the rate the bank posted when you opened the account.

Banks pay different rates for different term lengths. A six-month CD might pay 4.25% APY while a five-year CD from the same bank pays 5.10% APY. Longer terms usually pay more because the bank gets to hold your money longer. Online banks typically pay higher rates than brick-and-mortar branches because they have lower overhead costs. Credit unions sometimes offer competitive rates too, though you must be a member to open an account.

Key Takeaways

  • The interest you earn depends on the APY the bank offers, your deposit amount, and your CD term—all three matter equally.
  • Banks change their CD rates daily, so the rate available today may be different tomorrow.
  • Longer CD terms usually pay higher APY than shorter ones from the same institution.
  • Online banks typically offer higher rates than traditional banks because they spend less on physical branches.
  • Interest compounds on most CDs, meaning you earn interest on your interest if you leave it untouched until maturity.

How to calculate your actual earnings

The simplest way is to use the bank's own calculator, which most banks provide on their CD product page. You enter your deposit amount, the APY, and the term, and it shows you the total interest earned. If you want to do it yourself, the formula is: deposit amount × APY ÷ 365 days × number of days the CD is open. For a $10,000 CD at 4.75% APY for exactly one year (365 days), that's $10,000 × 0.0475 ÷ 365 × 365 = $475 in interest.

Most banks compound interest daily or monthly, which means they add earned interest back into your account and then pay interest on that new total. This compounds your earnings slightly—you make a small amount of interest on your interest. The difference is usually small for shorter terms but becomes noticeable on longer CDs. A $10,000 CD at 4.75% APY compounded daily earns about $486 over five years, while simple interest (no compounding) would earn $475 per year × 5 = $2,375 total. Compounding gets you to roughly $2,475—an extra $100 over the full term.

Why rates vary so much between banks

The Federal Reserve sets a target interest rate that influences what banks pay on savings products, but each bank decides its own CD rates within that environment. Online banks can afford to pay more because they don't maintain physical locations, staff, or ATM networks. A bank with 500 branches nationwide has higher costs than a bank with a website only, so it passes less of its revenue to depositors. Credit unions, which are member-owned nonprofits, sometimes pay higher rates because they return profits to members rather than shareholders.

Market conditions also matter. When the Fed raises its target rate, banks gradually increase CD rates. When the Fed cuts rates, CD rates fall. This happens over weeks or months, not overnight. A bank might also offer a promotional rate on new CDs for a limited time to attract deposits, then return to a lower standard rate once the promotion ends. Checking multiple banks before you open a CD can mean the difference between 4.25% APY and 5.00% APY—that's a meaningful gap on a large deposit.

What happens to your interest when the CD matures

When your CD reaches its maturity date, the bank adds all earned interest to your account. You then have a window—usually seven to ten calendar days—to decide what to do with the money. You can withdraw it, move it to another account at the same bank, or let the bank automatically renew it into a new CD at whatever rate the bank is offering that day. If you do nothing and the bank auto-renews, you're locked in at the new rate, which might be higher or lower than what you earned before.

Some banks charge a penalty if you withdraw money before the maturity date. This penalty is deducted from your interest earnings or principal. A $10,000 CD with a 150-day early withdrawal penalty might cost you $150 if you need the money after three months. The penalty amount varies by bank and CD term—longer CDs usually have larger penalties. Before opening a CD, check what the early withdrawal penalty is so you understand the cost of accessing your money early if an emergency happens.

How CD rates compare to other savings accounts

High-yield savings accounts currently pay rates in the same range as CDs—often 4.00% to 5.00% APY depending on the bank. The main difference is flexibility: you can withdraw from a savings account anytime without penalty, while a CD locks your money away. Money market accounts also pay competitive rates and offer limited check-writing, but again, you can access your funds whenever you need them. Regular savings accounts at traditional banks typically pay under 0.50% APY, which is why they're not competitive for money you're not using immediately.

CDs make sense when you have money you won't need for a specific period and want to may provide a fixed rate. If you might need the money within a year, a high-yield savings account is safer because there's no penalty for withdrawal. If you're saving for something specific—a down payment in three years, a car purchase in eighteen months—a CD with a matching term locks in your rate and removes the temptation to spend the money.

Understanding APY versus APR on CDs

Banks advertise CD rates as APY (annual percentage yield), not APR (annual percentage rate). APY includes the effect of compounding—it's the actual amount you'll earn in a year if you leave the money untouched. APR is just the stated rate without compounding factored in. For CDs, APY is the number that matters because it tells you the real earnings. If a bank shows you 4.75% APY, that's what you'll actually earn (assuming you hold the CD for the full year and don't withdraw early).

The difference between APY and APR becomes visible on longer terms. A five-year CD at 4.75% APY will earn more total interest than one at 4.75% APR because APY accounts for daily or monthly compounding. Most banks display APY prominently because it's the higher number and looks more attractive to depositors. When comparing CDs across banks, always compare APY to APY—never mix APY from one bank with APR from another, or you'll be comparing different things.

Frequently Asked Questions

Can I earn more interest by opening multiple CDs instead of one large one?

No. The interest rate is the same whether you deposit $5,000 in one CD or split it into five $1,000 CDs at the same bank. The only reason to open multiple CDs is to stagger maturity dates—for example, opening one CD every year so one matures each year and you have regular access to some of your money. This is called a CD ladder.

What if interest rates go up after I open my CD?

Your CD rate stays locked at what you agreed to when you opened it. If rates rise, you're earning less than new CDs pay. You can withdraw early and open a new CD at the higher rate, but you'll pay the early withdrawal penalty. Whether it's worth it depends on how much rates rose and how large your penalty is. Some people accept the lower rate rather than pay the penalty.

Do I pay taxes on CD interest?

Yes. The interest you earn on a CD is taxable income in the year you earn it. The bank will send you a 1099-INT form at tax time showing how much interest you earned. You report this on your tax return. This is one reason some people prefer CDs with shorter terms—you're not deferring taxes on a large sum for years.

Is my CD interest protected if the bank fails?

Yes, if the bank is FDIC-insured. The FDIC (Federal Deposit Insurance Corporation) protects up to $250,000 per depositor per bank, including both principal and accrued interest. If you have $100,000 in a CD earning $5,000 in interest, both amounts are covered up to the $250,000 limit. Credit union CDs are protected by the NCUA (National Credit Union Administration) with the same $250,000 limit.

Why would I choose a CD if a savings account pays almost the same rate?

A CD commits you to leaving money untouched, which removes the temptation to spend it. If you have a specific savings goal with a known timeline, a CD with a matching term guarantees you'll have that money available at the right time. Some people also find the fixed rate psychologically reassuring—you know exactly what you'll earn, with no surprises if rates drop.