What determines how much interest your CD earns

A CD pays interest based on three things: the annual percentage yield (APY) the bank offers, how much money you deposit, and how long you lock the money away. The bank sets the APY, and it changes constantly—sometimes daily. A CD that pays 4.5% APY one week might pay 4.25% the next week, depending on what the Federal Reserve does and what other banks are offering.

The longer you agree to leave your money untouched, the higher the APY usually is. A 3-month CD might pay 4.0% APY, while a 2-year CD from the same bank might pay 5.0% APY. The bank pays you more because you're giving up access to your money for longer. When you open the CD, the APY is locked in for the entire term—it won't change, even if rates drop or rise.

The actual dollars you earn depend on simple math: your deposit amount multiplied by the APY, divided by the number of days in a year. If you deposit $10,000 in a CD paying 5.0% APY for one year, you earn roughly $500 in interest (before any taxes). If you deposit the same amount for six months at the same rate, you earn roughly $250.

Key Takeaways

  • The APY a bank offers on CDs changes frequently and varies between banks, so comparing rates across multiple banks before opening a CD can mean earning hundreds of dollars more.
  • Longer CD terms almost always pay higher APY than shorter ones from the same bank, but your money is locked away and you cannot access it without a penalty.
  • The interest you earn is calculated on your full deposit amount for the entire term, and it compounds—meaning you earn interest on the interest the bank has already paid you.
  • Online banks typically pay higher APY on CDs than brick-and-mortar banks, sometimes 1% or more higher for the same term length.

How banks decide what APY to offer

Banks set CD rates based on what the Federal Reserve does with its benchmark interest rate. When the Fed raises rates, banks raise CD rates. When the Fed cuts rates, CD rates fall. But banks don't move in lockstep—some move faster than others, and some offer higher rates than competitors to attract deposits.

Online banks almost always pay more than traditional banks. An online bank with lower overhead costs can afford to offer 5.25% APY on a 1-year CD while a bank with physical branches in your town offers 4.50% for the same term. This difference compounds: on a $25,000 deposit for one year, that 0.75% gap means $187.50 more in your pocket.

The bank's own funding needs also matter. If a bank needs deposits urgently, it raises rates to attract them. If deposits are flowing in naturally, the bank can afford to offer lower rates. This is why rates shift week to week, and why shopping around before you commit matters.

The difference between APY and interest rate

Banks quote two numbers: the interest rate and the APY. The interest rate is the raw percentage. The APY is what you actually earn, because it includes compounding—the process of earning interest on interest.

Most CDs compound interest daily or monthly. If your CD compounds daily, the bank calculates interest each day on your balance (including interest already paid), then adds it to your account. By the end of the year, you've earned slightly more than the simple interest rate alone would suggest. A CD with a 5.0% interest rate might have a 5.12% APY because of daily compounding.

Always compare APY, not the interest rate. The APY is the true number—it's what you'll actually receive when the CD matures.

How interest is paid out when your CD matures

When your CD term ends, the bank adds all the interest you've earned to your account. You then have a window—usually 7 to 10 days—to decide what to do with the money. You can withdraw it, move it to a savings account, or roll it into a new CD.

If you don't do anything during that window, most banks automatically renew your CD into a new term at whatever the current rate is. That new rate might be higher or lower than what you just earned. Read your CD agreement to see your bank's renewal policy, because rates can shift significantly between terms.

If you withdraw the money before the CD matures—before the term ends—you pay a early withdrawal penalty. This penalty is usually a certain number of months' worth of interest. A CD with a 6-month early withdrawal penalty means you lose 6 months of interest if you take the money out early. On a $10,000 CD paying 5.0% APY, that's roughly $250 gone.

Why some CDs pay more than others

The biggest factor is the term length. A 5-year CD pays more APY than a 1-year CD from the same bank because you're locking your money away longer. The bank can invest that money for five years with certainty, so it shares some of that benefit with you in the form of higher interest.

The second factor is the bank itself. Online banks pay more than traditional banks. Credit unions sometimes pay more than commercial banks. Banks in competitive markets pay more than banks in less competitive areas. A $10,000 CD at an online bank might earn $550 in a year, while the same deposit at a traditional bank earns $425—a difference of $125 for doing nothing except choosing a different institution.

The third factor is timing. Rates are always moving. If you open a CD when rates are near their peak, you lock in a higher rate. If you open one when rates are falling, you lock in a lower rate. You cannot predict where rates will go, but you can watch the trend and act when rates look attractive.

Calculating what you'll actually earn

The formula is straightforward: Deposit × APY ÷ 365 × Number of Days = Interest Earned. If you deposit $5,000 in a CD paying 4.75% APY for 180 days, the math is: $5,000 × 0.0475 ÷ 365 × 180 = roughly $117.

Most banks show you the projected interest before you open the CD. You enter your deposit amount and term length, and the bank displays how much interest you'll earn. Use this tool to compare CDs across banks. A difference of 0.5% APY on a $50,000 deposit for one year is $250—real money worth a few minutes of comparison shopping.

Remember that the interest you earn is taxable income. If you earn $500 in CD interest in a calendar year, you'll report that on your tax return. The bank will send you a 1099-INT form in January showing how much interest you earned. This doesn't change how much the bank pays you, but it affects how much you keep after taxes.

When a CD makes sense versus other savings options

A CD makes sense when you have money you won't need for a specific period—six months, one year, three years. You lock in a rate, and that rate is may provide. A high-yield savings account pays interest too, but the rate can drop at any time. If you open a savings account at 4.5% APY and rates fall to 3.0%, your rate falls with it. A CD protects you from that risk.

The trade-off is access. You cannot touch CD money without a penalty. If you might need the money in an emergency, a savings account is safer. If you're certain you won't need it, a CD usually pays more.

Money market accounts sit in the middle—they pay more than regular savings accounts but less than CDs, and they let you withdraw money (though sometimes with limits). The right choice depends on when you'll need the money and how much you value may provide interest versus flexibility.

Frequently Asked Questions

Do I pay taxes on CD interest?

Yes. CD interest is taxable income in the year you earn it, even if you don't withdraw the money until the CD matures. The bank sends you a 1099-INT form showing how much interest you earned, and you report it on your tax return. The interest is taxed as ordinary income at your regular tax rate.

Can I lose money in a CD?

No. CDs are insured by the FDIC (Federal Deposit Insurance Corporation) up to $250,000 per depositor per bank. Your principal is safe. The only way to lose money is if you withdraw early and the early withdrawal penalty exceeds the interest you've earned, which is rare on longer-term CDs.

What happens if I need my money before the CD matures?

You can withdraw it, but you'll pay an early withdrawal penalty. The penalty amount varies by bank and CD term—it's usually three to six months of interest. On a $10,000 CD paying 5.0% APY with a 6-month penalty, withdrawing after three months costs you roughly $250 in lost interest.

Should I open multiple CDs with different maturity dates?

Some people do this, called a "CD ladder," so money matures at different times and they can reinvest it as rates change. If you open five 1-year CDs at different times, one matures every few months, giving you flexibility without locking all your money away for five years. This strategy works best when you have a larger amount to split.

Why would I choose a short-term CD if it pays less?

If you think interest rates will rise soon, a short-term CD lets you reinvest at a higher rate when it matures. If you might need the money within a year, a short-term CD has a smaller penalty if you withdraw early. And if you're uncertain about locking money away, a short term is less risky psychologically.