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

When you put money in a savings account, the bank lends that money to other customers as mortgages, car loans, and business loans. The bank charges those borrowers interest on those loans. The bank keeps most of that interest, but pays you a small portion as a reward for depositing your money there. That payment to you is called interest, and it gets added to your account balance automatically.

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 offers. A higher interest rate means you earn more. A larger balance means you earn more. Money that sits in the account longer earns more interest than money that moves out quickly.

Interest rates change constantly and vary widely between banks. A savings account at one bank might pay 4.5% annually while another pays 0.01%. The difference between those two rates means you could earn 450 times more money in the higher-rate account with the same balance. Shopping around for the best rate is worth the time.

Key Takeaways

  • Banks pay you interest on savings account balances because they lend your money to other customers and keep most of the interest those borrowers pay.
  • Your interest earnings depend on three factors: your account balance, the interest rate the bank offers, and how long your money stays in the account.
  • Interest rates vary dramatically between banks—from less than 0.01% to over 5%—so comparing rates before opening an account can mean hundreds of dollars in difference over a year.
  • Interest compounds, meaning you earn interest on your interest, so money that stays untouched grows faster than money you withdraw regularly.
  • Online banks typically offer higher rates than brick-and-mortar banks because they have lower overhead costs.

How interest rates are set and why they change

Banks set their own interest rates based on what the Federal Reserve does. The Federal Reserve is the central bank of the United States, and it sets a target range for the interest rate that banks charge each other for overnight loans. When the Fed raises its rate, banks usually raise the rates they offer on savings accounts. When the Fed lowers its rate, savings account rates typically fall.

Banks also look at what competitors are offering. If one bank raises its savings rate to attract more deposits, other banks often follow. During periods when the Fed is raising rates—like 2022 and 2023—savings rates climbed quickly. When the Fed stops raising or starts cutting rates, savings rates fall more slowly because banks are reluctant to lower what they pay depositors.

The rate you see advertised is called the Annual Percentage Yield, or APY. This is the actual percentage of your balance you will earn over one year, including the effect of compounding. It is different from the interest rate itself, which does not account for compounding. Always compare APY between accounts, not the interest rate alone.

How compounding makes your money grow faster

Compounding means you earn interest on your interest. Here is how it works: suppose you have $1,000 in an account earning 4% APY. After one month, the bank adds about $3.33 to your balance (one-twelfth of 4% of $1,000). Your new balance is $1,003.33. The next month, the bank calculates interest on $1,003.33, not the original $1,000. You earn slightly more the second month than the first.

Over years, compounding creates a real difference. A $10,000 deposit earning 4% APY grows to $10,412 after one year with monthly compounding. Without compounding—if the bank just paid you $400 once at the end of the year—you would have $10,400. The extra $12 comes from earning interest on interest. The longer your money sits, the more compounding matters. After 10 years at 4% APY, that $10,000 grows to $14,802 with compounding, versus $14,000 without it.

Most savings accounts compound interest daily or monthly. Daily compounding earns slightly more than monthly compounding, but the difference is small. What matters far more is the APY itself—a 5% account with monthly compounding beats a 2% account with daily compounding.

The difference between savings accounts and money market accounts

A money market account is a hybrid between a savings account and a checking account. It typically pays a higher interest rate than a regular savings account, but requires a larger minimum balance—often $2,500 to $10,000. Money market accounts also come with a debit card or checkbook, so you can withdraw money more easily than from a savings account.

The tradeoff is that money market accounts usually limit how many withdrawals you can make per month. Federal rules once capped withdrawals at six per month, though that rule is no longer enforced. Individual banks still impose limits, often allowing three to six withdrawals monthly. If you exceed the limit, the bank may charge a fee or convert your account to a checking account.

If you need to access your money frequently, a regular savings account is simpler. If you have a large balance you will not touch for months, a money market account's higher rate might be worth the withdrawal limits and minimum balance requirement.

Why online banks pay more interest than traditional banks

Online banks—banks with no physical branches—consistently offer higher interest rates than banks with brick-and-mortar locations. The reason is straightforward: online banks have much lower overhead costs. They do not pay rent on branch buildings, do not employ tellers, and do not maintain the infrastructure of a physical network. They pass those savings to customers through higher interest rates.

An online bank might pay 4.5% APY on a savings account while a traditional bank in your town pays 0.05% on the same balance. Over one year, a $10,000 deposit earns $450 at the online bank and $5 at the traditional bank. The difference compounds over time.

Online banks are insured by the Federal Deposit Insurance Corporation, or FDIC, just like traditional banks. Your money is equally safe. The only real disadvantage is that you cannot walk into a branch to deposit cash or speak to someone in person. Most online banks let you deposit checks by phone camera and transfer money from other accounts electronically.

How to calculate what you will earn

You can estimate your interest earnings with a simple formula. Multiply your balance by the APY, then divide by 12 to get your monthly earnings. A $5,000 balance at 4% APY earns about $16.67 per month ($5,000 × 0.04 ÷ 12). After one year, you would have roughly $5,200.

This is an approximation because it does not account for daily compounding or the fact that your balance might change during the year. For a precise calculation, use a savings calculator—most banks provide one on their website. You enter your starting balance, the APY, how often interest compounds, and how long you plan to keep the money. The calculator shows you the exact amount you will have at the end.

If you plan to add money to your account regularly, the calculator becomes even more useful. It can show you the difference between adding $100 per month versus $200 per month, or between a 3% rate and a 5% rate. Seeing the numbers side by side helps you decide whether switching banks or increasing your deposits is worth the effort.

What happens to your interest if you withdraw money early

Withdrawing money from a savings account does not trigger a penalty or loss of interest, unlike certificates of deposit (CDs), which do penalize early withdrawal. When you withdraw from a savings account, the bank simply stops paying interest on the amount you removed. The interest you already earned stays in your account.

If you have $5,000 earning 4% APY and withdraw $2,000 after six months, you keep the interest you earned on the full $5,000 during those six months. Going forward, the remaining $3,000 earns interest at the same 4% rate. There is no fee, no lost interest, and no penalty.

This is why savings accounts are good for money you might need soon. If you are certain you will not touch the money for years, a CD often pays a higher rate. But if there is any chance you will need it, a savings account lets you access it without losing earnings.

Frequently Asked Questions

Do I have to pay taxes on the interest I earn?

Yes. Interest income is taxable as ordinary income. If you earn $100 or more in interest during the year, the bank sends you a 1099-INT form in January, and you report that income on your tax return. Interest earned in a traditional IRA or 401(k) is not taxed until you withdraw the money, but interest in a regular savings account is taxed in the year you earn it.

Why is my savings account earning almost no interest?

Your bank is probably offering a rate far below the market rate. Many traditional banks pay 0.01% to 0.05% on savings accounts because they assume customers will not shop around. Online banks and credit unions often pay 4% to 5% on the same type of account. Switching banks takes about 15 minutes and can earn you hundreds of dollars per year.

Can I lose money in a savings account?

No. Your balance is protected by FDIC insurance up to $250,000 per account holder per bank. Even if the bank fails, you get your money back. The only way your balance shrinks is if you withdraw money or if fees exceed your interest earnings—which happens only at banks with high fees and very low rates.

What is the difference between APY and APR?

APY (Annual Percentage Yield) includes the effect of compounding and shows what you actually earn. APR (Annual Percentage Rate) does not include compounding and is used mainly for loans and credit cards. Always compare savings accounts using APY, not APR.

Does the amount of interest I earn depend on how often I check my balance?

No. Checking your balance does not affect how much interest you earn. Interest accrues based on your balance and the APY, regardless of whether you look at your account once a year or ten times a day. Frequent checking might tempt you to withdraw money, which would reduce your balance and future earnings, but the checking itself has no effect.