The interest you earn depends on the bank's rate and how much money you keep in the account

The amount of interest a savings account earns is not fixed — it changes based on two things: the annual percentage yield (APY) the bank offers, and the balance you maintain. A bank offering 4.5% APY on $10,000 will pay you roughly $450 per year, while the same rate on $1,000 pays about $45. The bank calculates this daily or monthly, depending on their terms, and deposits it into your account automatically.

The APY varies widely between banks. A large national bank might offer 0.01% APY on savings, while an online bank might offer 4.5% or higher on the same account type. The difference matters: at 0.01%, your $10,000 earns $1 per year. At 4.5%, it earns $450. That same $10,000 in a money market account or certificate of deposit (CD) at a different bank might earn even more, depending on the rate and how long you lock the money away.

Key Takeaways

  • Interest earned equals your account balance multiplied by the APY, divided by 12 months (or calculated daily, depending on the bank).
  • Online banks typically offer higher APY than traditional brick-and-mortar banks, sometimes 4% or more on savings accounts.
  • The APY can change at any time, so a rate that is high today may drop if the Federal Reserve lowers rates.
  • Money market accounts and CDs often pay more than regular savings accounts, but may require a larger deposit or lock your money away for a set period.

How banks calculate the interest you earn

Banks use your APY to figure out how much interest to pay you. The math is straightforward: take your balance, multiply it by the APY, and divide by 12 to get the monthly interest. If you have $5,000 at 4% APY, you earn roughly $16.67 per month ($5,000 × 0.04 ÷ 12). Some banks calculate daily instead, which means the interest compounds — you earn interest on your interest — but the yearly total is the same.

The catch is that your balance changes. If you deposit $2,000 mid-month, the bank may calculate interest only on the days that money was in the account. If you withdraw $1,000, your balance drops and so does the interest earned that month. Banks disclose exactly how they calculate this in their account terms, usually under "how interest is calculated" or "compounding frequency."

Why APY varies so much between banks

The Federal Reserve sets a benchmark interest rate that influences what banks pay on savings. When the Fed raises rates, banks can afford to pay more on savings accounts because they earn more from lending money out. When the Fed lowers rates, banks lower what they pay you. But banks do not all move at the same speed or to the same degree.

Online banks typically pay more than traditional banks because they have lower overhead costs — no physical branches, fewer employees. A bank like Ally or Marcus can offer 4.5% APY while Chase or Bank of America offer 0.01% on the same type of account. The trade-off is that online banks have no branch to visit in person, though most offer phone and chat support. If you want a higher rate, you usually have to move your money to an online bank or credit union.

How to compare rates across different banks

The APY is the only number you need to compare savings accounts fairly. Ignore the interest rate (APR) — use APY, which includes compounding and shows the true annual return. Write down the APY for each bank you are considering, along with any fees or minimum balance requirements. A bank offering 4.5% APY with no fees is better than one offering 4.6% APY but charging $10 per month.

Check the bank's website directly rather than relying on comparison sites, because rates change frequently and websites sometimes lag. Most banks display the current APY prominently on their savings account page. If you cannot find it, call or chat with the bank — they are required to disclose it before you open an account. Write down the date you checked, because rates can shift within days.

What happens when interest rates change

Banks can change the APY on savings accounts at any time, with no notice required. If the Federal Reserve raises rates, your bank may raise your APY within days or weeks. If the Fed lowers rates, your bank may lower your APY just as quickly. You do not lose money you have already earned — interest that has been deposited stays in your account — but future interest will be calculated at the new, lower rate.

This is why the "best" savings account today may not be the best next month. A bank offering 4.5% might drop to 3.5% if the Fed cuts rates. Some people move their money to whichever bank is currently offering the highest rate, though this takes time and effort. Others pick a bank they trust and accept that the rate will fluctuate. There is no penalty for moving your money to a different bank, but you may have to wait a few business days for the transfer to complete.

Money market accounts and CDs as alternatives

If you want to earn more interest, you have options beyond a regular savings account. A money market account is a hybrid between a savings account and a checking account — it usually pays a higher APY than savings but may require a larger minimum balance (often $2,500 or more). You can write checks or use a debit card, but the bank may limit how many withdrawals you make per month.

A certificate of deposit (CD) locks your money away for a set period — typically three months to five years — in exchange for a higher APY. If you withdraw the money early, you pay a penalty, usually a few months' worth of interest. CDs make sense if you know you will not need the money for a specific amount of time and want to lock in a rate before it drops. A one-year CD at 5% APY is worth considering if you have money sitting idle and do not plan to touch it.

Frequently Asked Questions

Can I lose money in a savings account?

No. The bank cannot take money from your account without your permission, and the Federal Deposit Insurance Corporation (FDIC) insures up to $250,000 per account. You earn interest, not lose it. The only way your balance shrinks is if you withdraw money or the bank charges a fee.

Is the interest taxable?

Yes. Interest earned on savings accounts is taxable income. If you earn $100 in interest during the year, you report it on your tax return. The bank will send you a 1099-INT form in January if you earned $10 or more. This is one reason why high-yield savings accounts matter — earning 4% instead of 0.01% means more money after taxes.

Why do some banks offer much higher rates than others?

Online banks have lower costs and can pass those savings to customers through higher APY. Traditional banks with physical branches have more overhead and typically pay less. Both are safe — as long as the bank is FDIC-insured, your money is protected up to $250,000.

What is the difference between APY and APR?

APY includes compounding (interest earned on interest), while APR does not. For savings accounts, always compare using APY. APR is used for loans and credit cards. Banks are required to show you the APY before you open an account.

Should I move my money if another bank offers a higher rate?

It depends on how much money you have and how much the rate difference is. Moving $10,000 from 0.5% APY to 4.5% APY saves you $400 per year. The transfer takes a few business days, but there is no penalty. If the amount is small or you value convenience over rate, staying put is fine.