What determines how much interest you earn

The amount of interest your savings account earns depends on three things: the annual percentage yield (APY) your bank offers, how much money you keep in the account, and how long it stays there. A bank with a 4.5% APY will pay you roughly 4.5 times more interest per year than a bank offering 0.01% APY on the same balance. The difference between a high-yield savings account and a traditional bank account can mean hundreds or thousands of dollars per year on the same deposit.

Interest compounds, which means you earn interest on the interest you already earned. Most savings accounts compound daily or monthly. If you deposit $10,000 at 4.5% APY compounded daily, you will earn roughly $450 in the first year—but the second year you will earn interest on $10,450, not just the original $10,000. Over time, compounding makes a real difference, especially if you leave money untouched for years.

Banks set their own APY rates based on what the Federal Reserve charges them to borrow money. When the Fed raises rates, banks eventually raise what they pay on savings. When the Fed cuts rates, banks cut what they pay. This means the APY you see today may be different in three months or six months.

Key Takeaways

  • Your interest earnings equal your account balance multiplied by the APY, divided by 365 days, then multiplied by the number of days your money sits in the account.
  • High-yield savings accounts currently pay between 4% and 5.35% APY, while traditional bank savings accounts often pay 0.01% to 0.05% APY.
  • Interest compounds daily or monthly at most banks, meaning you earn interest on interest, which accelerates growth over time.
  • APY rates change when the Federal Reserve changes its benchmark rate, so the rate you lock in today may not be the rate you earn next quarter.
  • Moving money to a higher-APY account can earn you hundreds more dollars per year on the same balance without any additional work.

How to calculate your own interest earnings

The basic formula is: Balance × APY ÷ 365 × Number of Days = Interest Earned. If you have $25,000 in an account paying 4.5% APY and you leave it there for one full year, you earn roughly $1,125. If you leave it for six months, you earn roughly $562.50.

Most banks show you the interest you earned in your monthly or quarterly statement. You can also use an online savings calculator by typing your balance, the APY, and the time period into a search engine. These calculators account for daily compounding automatically, so the result will be slightly higher than the simple formula above.

If you make deposits or withdrawals during the year, the calculation becomes more complex because interest is calculated on the average balance or the daily balance, depending on the bank's method. Some banks calculate interest on the lowest balance you held during the month; others calculate on the average balance across all days. Read your account agreement or call the bank to find out which method they use, because it affects how much you earn.

Why different banks pay different rates

Banks that operate only online—like Marcus, Ally, and American Express Personal Savings—typically pay higher APY than brick-and-mortar banks because they have lower overhead costs. They do not maintain physical branches, so they pass those savings to customers in the form of higher interest rates. A traditional bank like Chase or Bank of America may pay 0.01% APY on savings, while an online bank pays 4.75% APY on the same type of account.

Credit unions sometimes pay higher rates than banks, though not always. Credit unions are member-owned cooperatives, so they may return profits to members through better rates. However, credit unions vary widely in what they offer, so you need to check your specific credit union's rate.

Banks also offer different rates for different account types. Money market accounts sometimes pay more than regular savings accounts. Certificates of deposit (CDs) lock your money away for a set period—three months, one year, five years—and pay a higher rate in exchange for that commitment. If you need access to your money, a CD is not the right choice, but if you know you will not touch the money for two years, a two-year CD might pay 4.8% while a regular savings account pays 4.5%.

How rate changes affect what you earn

When the Federal Reserve raises its benchmark interest rate, banks eventually raise the APY they pay on savings accounts. This usually happens within days or weeks, not months. When the Fed cuts rates, banks cut what they pay on savings much faster—sometimes within hours. This asymmetry means you benefit quickly when rates rise, but lose out quickly when they fall.

If you locked money into a CD at 5.0% APY for two years, you keep earning 5.0% for the full two years, even if rates drop to 2.0% next month. That is the trade-off: you give up the ability to move your money in exchange for a may provide rate. If you keep money in a regular savings account, your rate can change at any time, which means you could earn more if rates rise, but you could also earn less if rates fall.

Checking your bank's current APY once a quarter is worth doing. If your bank drops its rate significantly and competitors are paying much more, moving your money takes about 15 minutes and can earn you hundreds more per year.

The difference between APY and APR

APY (annual percentage yield) includes the effect of compounding and tells you the true annual return on a savings account. APR (annual percentage rate) does not include compounding and is used for loans and credit cards. For savings accounts, always look at APY, not APR. A savings account advertising 4.5% APY will earn you more than one advertising 4.5% APR because APY accounts for daily or monthly compounding.

Banks are required by law to display APY prominently when advertising savings rates, so you should see it clearly on their website or in marketing materials. If you see only APR or a rate without a label, that is a red flag—call the bank and ask for the APY before opening an account.

When a higher rate is not worth it

If you are moving money between accounts frequently, the time and effort may not be worth a 0.5% rate difference on a small balance. If you have $2,000 and move it from a 4.0% account to a 4.5% account, you earn an extra $10 per year. That is real money, but it may not justify the hassle if the new bank has a clunky app or charges fees.

Some banks charge monthly maintenance fees, overdraft fees, or fees for transfers. These fees can wipe out the interest you earn. Before opening an account for the rate alone, check whether the bank charges fees and whether you can waive them by maintaining a minimum balance or setting up direct deposit.

If you need the money within the next few months, putting it in a CD to earn a slightly higher rate locks it away and may charge you a penalty if you withdraw early. A regular savings account with a lower rate but instant access is often the better choice for money you might need soon.

Frequently Asked Questions

How often do banks compound interest on savings accounts?

Most banks compound interest daily, which means they calculate and add interest to your account every single day. Some compound monthly or quarterly. Daily compounding earns you slightly more because you earn interest on interest more frequently. The difference is small on low balances but adds up on larger amounts over years.

Can I earn interest on money in a checking account?

Some checking accounts pay interest, but the rate is almost always much lower than a savings account—often 0.01% or less. If you have money sitting in a checking account that you do not need for bills, moving it to a savings account earning 4.5% will earn you hundreds more per year. Keep only what you need for monthly expenses in checking.

What happens to my interest if I withdraw money before the year ends?

You earn interest only on the money that was actually in the account. If you deposit $10,000 and withdraw $5,000 after six months, you earn interest on $10,000 for six months and $5,000 for the remaining six months. The bank calculates this automatically—you do not need to do anything.

Is the APY I see today may provide for the next year?

No. Banks can change the APY on savings accounts at any time without notice. The rate you see when you open an account may be different next month. CDs are different—when you open a CD, the rate is locked in for the full term, whether rates rise or fall.

Do I pay taxes on the interest I earn?

Yes. Interest earned on savings accounts is taxable income. Banks send you a 1099-INT form each January showing how much interest you earned the previous year. You report this on your tax return. The more interest you earn, the more you owe in taxes, though the tax rate depends on your overall income.