Interest is money the bank pays you for letting them use your deposits

When you put money in a savings account, the bank lends that money out to other customers as mortgages, car loans, and business loans. The bank keeps the difference between what it pays you and what it charges borrowers. That payment to you is interest—usually expressed as an annual percentage rate, or APR.

The amount you earn depends on three things: how much money sits in your account, what interest rate the bank offers, and how long the money stays there. A bank offering 4.5% APR on a $10,000 balance will pay you roughly $450 per year, though the exact amount depends on how the bank calculates and compounds the interest.

Interest rates vary widely between banks and account types. Online banks often pay higher rates than brick-and-mortar branches because they have lower overhead costs. Rates also change based on what the Federal Reserve does—when the Fed raises its benchmark rate, banks typically raise savings rates within weeks or months. When the Fed cuts rates, savings rates fall.

Key Takeaways

  • Banks pay you interest as a percentage of your balance, calculated daily or monthly and added to your account on a schedule set by the bank.
  • The interest rate you receive depends on the bank, the account type, and the current Federal Reserve rate environment.
  • Compound interest means you earn interest on your interest, which accelerates growth over time.
  • Money market accounts and certificates of deposit (CDs) often pay higher rates than regular savings accounts because you agree to restrictions on withdrawals.
  • The FDIC insures up to $250,000 per account holder per bank, so interest earnings are protected even if the bank fails.

How banks calculate the interest you earn

Banks use one of two methods to calculate interest: simple interest or compound interest. Simple interest is rare in savings accounts today. It calculates interest only on your original deposit, not on interest you have already earned. If you deposited $10,000 at 4% simple interest, you would earn $400 the first year and $400 every year after, regardless of how much interest accumulated.

Compound interest is what most savings accounts use. The bank calculates interest on your balance plus any interest already earned. If that same $10,000 earns 4% compounded annually, you earn $400 in year one. In year two, you earn 4% on $10,400, which is $416. The interest grows faster because you are earning returns on your returns.

The frequency of compounding matters. Banks may compound interest daily, monthly, quarterly, or annually. Daily compounding grows your money faster than annual compounding at the same rate, because interest gets added to your balance more often. Most online savings accounts compound daily, which is why they tend to show higher effective yields than accounts that compound monthly or quarterly.

When and how the bank deposits your interest

Banks calculate interest continuously but deposit it on a schedule. Most savings accounts add interest monthly—on the first day of the month or on your account anniversary. Some add it quarterly. A few high-yield accounts add it daily, though the amount added each day is tiny.

Once interest is deposited, it becomes part of your balance and earns interest itself in the next compounding period. This is why leaving money untouched in a savings account for years produces noticeably more growth than withdrawing and redepositing frequently.

You will see the interest posted in your account history. The bank also reports it to the IRS on a Form 1099-INT if you earn $10 or more in a year. You owe federal income tax on all interest earned, even if you do not withdraw it.

Why interest rates differ between account types

A regular savings account typically pays the lowest rate because you can withdraw money anytime without penalty. The bank cannot reliably plan how long it will have your money, so it pays less for that uncertainty.

Money market accounts usually pay higher rates than savings accounts but come with limits on how many times per month you can withdraw. Certificates of deposit (CDs) pay the highest rates because you agree to lock your money away for a set term—three months, six months, one year, five years, or longer. The longer the term, the higher the rate. If you withdraw before the term ends, you pay a penalty that eats into your earnings.

High-yield savings accounts are regular savings accounts offered by online banks at rates much higher than traditional banks. They have no lock-in period and no withdrawal limits, yet they pay rates competitive with CDs. This is possible because online banks have lower costs and can pass savings to customers.

How to compare interest rates across banks

Interest rates change constantly. A bank offering 4.75% today might drop to 4.50% next month if the Fed cuts rates. Before opening an account, check the current rate on the bank's website—not the rate from an article or comparison site, which may be outdated.

Look for the Annual Percentage Yield (APY), not just the APR. APY includes the effect of compounding, so it shows the true amount you will earn. A bank advertising 4.5% APR compounded daily might have an APY of 4.60%, which is what you actually receive.

Compare rates across multiple banks. Online banks like Marcus, Ally, and American Express Personal Savings often lead on rates, but credit unions and some regional banks occasionally match or beat them. The difference between 4.5% and 5.0% on $50,000 is $250 per year—worth the five minutes it takes to shop around.

What happens to interest if you withdraw money early

Withdrawing from a regular savings account does not trigger a penalty, but it does reduce the balance earning interest. If you withdraw $5,000 from a $20,000 account, next month's interest will be calculated on $15,000, not $20,000. The interest you already earned stays in your account.

CDs are different. If you withdraw before the maturity date, the bank charges an early withdrawal penalty. The penalty amount varies by bank and CD term—typically three to six months of interest, though some charge a percentage of the principal. A $10,000 CD earning 5% with a six-month penalty means you lose roughly $250 if you cash out early. In some cases, the penalty can exceed the interest earned, leaving you with less than you deposited.

Money market accounts have withdrawal limits (usually six per month) but no early withdrawal penalty. Exceeding the limit may result in a fee or conversion to a regular savings account at a lower rate.

How inflation affects what your interest earnings are actually worth

Interest earnings are real money added to your account, but inflation reduces their purchasing power. If you earn 4% interest but inflation is 3%, your money's real growth is only about 1%. During periods of high inflation, even high-yield savings rates may not keep pace with rising prices.

This is why interest rates matter most when they exceed inflation. In 2023 and 2024, savings rates climbed above 4% while inflation cooled to around 3%, making savings accounts genuinely valuable for preserving wealth. In other periods, rates lag inflation, and your money loses buying power even as the account balance grows.

For money you need within a few years, a high-yield savings account or short-term CD still protects your principal and beats inflation most of the time. For longer time horizons, other investments like stocks or bonds may offer better growth, though they carry more risk.

Frequently Asked Questions

Do I have to pay taxes on savings account interest?

Yes. All interest earned is taxable income at your federal tax rate. If you earn $50 or more in a year, the bank sends you a Form 1099-INT. You report this on your tax return even if you did not withdraw the money. State income tax may also apply depending on where you live.

Can a bank lower my interest rate after I open an account?

Yes. Banks can change savings account rates anytime without notice. CD rates are locked in for the term, so a bank cannot lower your rate on an existing CD. But once the CD matures, the new rate offered may be lower or higher than what you earned before.

What is the difference between APR and APY?

APR is the annual interest rate before compounding. APY includes the effect of compounding and shows the true annual return. At the same APR, daily compounding produces a higher APY than monthly compounding. Always compare APY when shopping for accounts.

Is my interest earnings protected if the bank fails?

Yes. The FDIC insures deposits up to $250,000 per account holder per bank, including both your principal and any interest earned. If a bank fails, the FDIC pays you the full amount up to the limit. Interest continues to accrue up to the date of the bank's closure.

Why do online banks pay more interest than traditional banks?

Online banks have lower overhead—no physical branches, fewer employees, lower rent. They pass these savings to customers through higher interest rates. They also compete aggressively on rate to attract deposits since they cannot rely on local foot traffic.