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

When you put money in a savings account, the bank takes that money and lends it out to other customers as mortgages, car loans, and business loans. The bank charges those borrowers interest on those loans. The bank then pays you a portion of that interest as a reward for depositing your money there. That payment to you is called account interest.

The amount you earn depends on three things: how much money you have in the account, how long it stays there, and the interest rate the bank is currently offering. Banks change their rates frequently—sometimes weekly—based on what the Federal Reserve does with its own rates. A rate that was 4.5% last month might be 4.25% this month, or it might stay the same.

Interest accrues, meaning it builds up over time. Most savings accounts calculate interest daily but deposit it into your account monthly. Some accounts compound interest, which means the interest you earn also starts earning interest. The more often interest compounds, the more you earn overall.

Key Takeaways

  • Banks pay you interest because they lend out your deposits to other customers and share a portion of what they collect in return.
  • Your interest earnings depend on your account balance, how long the money stays deposited, and the bank's current interest rate.
  • Interest rates change frequently and vary widely between banks—a high-yield savings account might pay 4% while a standard account pays 0.01%.
  • Interest usually accrues daily but is added to your account monthly, and compound interest means your earnings start earning interest too.
  • You can see your interest earnings on your monthly statement or by logging into your online banking portal.

How the interest rate is set and why it changes

Banks do not decide interest rates in a vacuum. The Federal Reserve, which is the central bank of the United States, sets a target range for what banks charge each other to borrow money overnight. When the Fed raises that range, banks typically raise the rates they offer on savings accounts. When the Fed lowers it, savings rates usually fall too.

Banks also compete with each other. If one bank offers 4.5% on a high-yield savings account and another offers 3%, customers move their money to the higher rate. This competition pushes rates up. During periods when the Fed is raising rates, you will see savings rates climb. During periods when the Fed is cutting rates, savings rates drop.

The type of account also matters. A standard savings account at a large bank might pay 0.01% because the bank assumes you will keep your money there regardless. A high-yield savings account at an online bank might pay 4% or higher because online banks have lower overhead costs and need to attract deposits to compete with brick-and-mortar banks.

How to calculate what you will earn

The basic formula is: (Account Balance × Annual Interest Rate) ÷ 365 = Daily Interest Earned. If you have $10,000 in an account paying 4% annual interest, you earn about $1.10 per day. Over a month, that is roughly $33. Over a year, it is $400.

That calculation assumes your balance stays the same all year. In reality, you probably deposit and withdraw money. Banks handle this by calculating interest on your daily balance. If you have $10,000 on day one and deposit $5,000 on day fifteen, the bank calculates interest on $10,000 for fourteen days and $15,000 for the remaining days of the month.

Compound interest changes the math. If your account compounds monthly, the interest you earn in month one gets added to your balance, and in month two you earn interest on both your original deposit and the interest from month one. Over years, this effect grows. A $10,000 deposit at 4% compounded daily will earn more than the same deposit at 4% compounded monthly, though the difference is usually small for savings accounts.

Where to find your interest earnings

Your bank sends you a statement each month—either by mail or email, depending on your settings—that shows all deposits, withdrawals, and interest earned. The interest appears as a single line item, usually labeled "Interest Paid" or "Interest Earned." This is the actual money the bank deposited into your account that month.

You can also check your balance and interest earnings anytime by logging into your online banking portal or mobile app. Most banks show a running total of interest earned year-to-date. At the end of the year, your bank will send you a 1099-INT form if you earned $10 or more in interest. You will need this form to report the interest on your federal tax return, because interest income is taxable.

Some banks let you set up alerts when interest is deposited, so you can watch your earnings accumulate. This is purely informational—the interest is already yours once it hits your account.

Why some accounts earn more interest than others

The biggest factor is the bank's business model. Online banks like Marcus, Ally, and Wealthfront have no physical branches, so they spend less on overhead. They pass those savings to customers by offering higher interest rates. A brick-and-mortar bank like Chase or Bank of America has thousands of branches and employees, so their costs are higher and their rates are typically lower.

Account type also matters. A money market account might pay slightly more than a standard savings account because you agree to keep larger balances. A certificate of deposit (CD) locks your money away for a set period—three months, one year, five years—and in exchange pays a higher rate. If you withdraw early, you pay a penalty.

Promotional rates are another factor. A new bank might offer 5% for the first three months to attract customers, then drop to 3.5% after that. Read the fine print to see when the promotional rate ends and what the regular rate will be.

What happens to your interest if rates drop

When the Federal Reserve cuts rates, banks lower their savings rates within days or weeks. If you are earning 4% and rates drop, your bank might lower your rate to 3.5% or 3%. Your existing balance does not disappear—you still have all your money—but the interest you earn going forward is less.

This is why some people move their money to banks offering higher rates when their current bank cuts rates. There is no penalty for moving money out of a savings account (unlike a CD). You can withdraw your balance anytime and deposit it at a bank paying more interest.

Conversely, when rates rise, your bank will eventually raise your rate too, though sometimes slowly. If you locked money into a CD before rates went up, you are stuck with the lower rate until the CD matures. This is a tradeoff of CDs: you get a may provide rate, but you miss out if rates climb.

How interest affects your taxes

Interest income is taxable. If you earned $100 in interest last year, that $100 counts as income on your federal tax return. Your bank reports this to the IRS on a 1099-INT form, and you report it on your return.

The tax you owe depends on your overall income and tax bracket. If you are in the 22% tax bracket and earn $500 in interest, you owe roughly $110 in federal tax on that interest (though state taxes may apply too). This is why high-yield savings accounts are more valuable than they first appear: earning 4% interest is better than earning 0.01%, even after taxes.

Some accounts, like Roth IRAs and traditional IRAs, let interest accumulate tax-free or tax-deferred. If you are saving for retirement, these accounts can be more efficient than a regular savings account because you do not pay taxes on the interest each year.

Frequently Asked Questions

Can I lose money if interest rates drop?

No. Your account balance never shrinks because rates fall. You simply earn less interest going forward. If you have $10,000 and rates drop from 4% to 2%, you still have $10,000—you just earn about $200 per year instead of $400.

Why does my bank pay almost no interest?

Large banks with many branches offer low rates because they do not need to compete aggressively for deposits—customers stay for convenience. Online banks offer much higher rates because they have no branches and need deposits to fund their lending. Switching to an online bank's savings account is usually free and takes a few days.

Is interest the same as APY?

No. Interest rate is the percentage the bank pays. APY (Annual Percentage Yield) is the actual amount you earn in a year after accounting for how often interest compounds. APY is always equal to or higher than the stated rate. Banks must show you the APY so you can compare accounts fairly.

What if I withdraw money before the month ends?

You still earn interest on the money you had in the account. If you deposit $5,000 on the first of the month and withdraw it on the fifteenth, you earn interest on $5,000 for fifteen days. The bank calculates this automatically.

Do I have to do anything to earn interest?

No. Interest accrues automatically once you open the account and deposit money. You do not need to take any action. The bank calculates and deposits interest into your account each month without you doing anything.