What determines how much interest you earn
The amount of interest you earn on a savings account depends on three things: the annual percentage yield (APY) the bank offers, how much money you keep in the account, and how long you leave it there. A bank might offer 4.5% APY on one account and 0.01% on another — the difference between these two is enormous over time, and it comes down to the type of account and the bank's own choice about what rate to pay.
The APY is the percentage of your balance the bank will pay you each year. If you have $1,000 in an account with 4.5% APY, the bank will pay you roughly $45 over twelve months (the exact amount depends on how often interest is added to your account, which varies by bank). If that same $1,000 sits in an account with 0.01% APY, you earn about 10 cents.
Banks set these rates based on what the Federal Reserve does with interest rates in the broader economy. When the Fed raises its rates, banks usually raise what they pay on savings accounts. When the Fed lowers rates, banks lower what they pay. This means the APY you see today may be different in six months.
Key Takeaways
- The APY printed on a savings account tells you what percentage of your balance the bank will pay you over one year, and this rate varies widely between banks and account types.
- Online banks typically offer higher APY than brick-and-mortar banks because they have lower costs, and you can compare rates across different banks before opening an account.
- Interest compounds — meaning you earn interest on the interest you already earned — and the more often it compounds, the slightly more you make, though the difference is usually small.
- The APY you see when you open an account is not locked in; banks can lower it at any time, though they usually give you notice before doing so.
- A savings account with 4% APY will roughly double your money in 18 years if you never touch it, while one with 0.01% APY will take over 7,000 years.
Why different banks pay different rates
Online banks — ones with no physical branches — almost always pay more interest than banks with buildings in your town. This is because online banks have much lower costs. They do not pay rent on a building, they do not employ tellers, and they do not maintain a network of ATMs. They pass those savings to you by paying higher APY on savings accounts.
A brick-and-mortar bank might pay 0.01% APY on a basic savings account, while an online bank pays 4.5% on the same type of account. Both are real banks with real deposit insurance, but the online bank's lower costs mean it can afford to pay you more.
Banks also pay different rates depending on what type of account you open. A high-yield savings account pays much more than a regular savings account at the same bank. A money market account may pay slightly more than a savings account but usually requires you to keep a larger balance. A certificate of deposit (CD) locks your money away for a set time — three months, one year, five years — and pays a higher rate in exchange for that lock-in.
How to calculate what you will earn
The simplest way is to multiply your balance by the APY. If you have $5,000 and the APY is 4%, you will earn roughly $200 in one year: $5,000 × 0.04 = $200. This is an approximation because interest usually compounds — the bank adds interest to your account monthly or daily, and then you earn interest on that interest in the next period.
If interest compounds monthly, you earn slightly more than the straightforward calculation shows. If it compounds daily, you earn a bit more still. But the difference is usually small. On $5,000 at 4% APY compounded daily versus compounded monthly, you might earn an extra dollar or two over the year.
Most banks show you a calculator on their website where you can enter your balance and see what you will earn. You can also use an online savings calculator — search "savings account interest calculator" — to compare what different rates would earn you over different time periods. This is useful when you are deciding between banks.
Why the rate you see today might change
Banks are not required to keep the APY the same forever. They can lower it at any time, though federal rules require them to give you notice before they do — usually at least 21 days. Some banks lower rates frequently; others hold them steady for months.
The rate changes because the Federal Reserve changes its own rates, and banks adjust what they pay on savings accounts in response. When the Fed raises rates, banks raise what they pay you. When the Fed lowers rates, banks lower what they pay. This means a 4.5% APY today might become 3.5% in six months if the Fed cuts rates.
You can move your money to a different bank if your current bank lowers its rate too much. There is no penalty for closing a savings account and opening one elsewhere. Many people move their money between banks to chase the highest available rate.
The difference between APY and APR
You will see two abbreviations: APY and APR. For a savings account, always look at the APY. APY stands for annual percentage yield and includes the effect of compounding — it tells you the real amount you will earn. APR stands for annual percentage rate and does not include compounding.
Banks are required to show you the APY on savings accounts, so that is what you will see in most places. APR is used for loans and credit cards, not savings accounts. If a savings account page shows only APR, that is a sign the bank is being unclear, and you should look elsewhere.
How much you actually earn over time
The longer you leave money in a savings account, the more the difference between high and low rates matters. A $10,000 balance earning 0.01% APY grows to about $10,010 after one year. The same $10,000 at 4.5% APY grows to about $10,450 after one year — a difference of $440 in a single year.
Over five years, that gap widens. At 0.01%, your $10,000 becomes about $10,050. At 4.5%, it becomes about $12,462. Over ten years, 0.01% gives you $10,100, while 4.5% gives you about $15,530.
This is why shopping around for the highest APY matters, especially if you are saving money for a goal that is years away. The difference between a bank paying 0.01% and one paying 4.5% is not just a few dollars — it is thousands of dollars over time.
Frequently Asked Questions
Is the interest I earn on a savings account taxed?
Yes. Interest earned on a savings account is taxable income. At the end of each year, your bank will send you a form called a 1099-INT if you earned $10 or more in interest. You report this on your tax return. The amount you owe in taxes depends on your overall income and tax bracket.
Can a bank lower my interest rate without telling me?
No. Federal rules require banks to give you at least 21 days' notice before lowering the APY on a savings account. The notice can come by mail, email, or through your online banking portal. You have the right to close the account before the new rate takes effect.
What happens to my interest if I withdraw money before the year is over?
You earn interest only on the money that sits in the account. If you deposit $5,000 and withdraw $2,000 after six months, you earn interest only on the $5,000 for those six months, then on the remaining $3,000 for the rest of the year. Interest accrues daily at most banks, so you get paid for every day the money was there.
Is there a limit to how much interest I can earn?
No. You can earn as much interest as your balance and the APY allow. There is no cap on interest earnings. However, the Federal Deposit Insurance Corporation (FDIC) insures only up to $250,000 per account at each bank, so if you have more than that, you should split it across multiple banks to keep it all insured.
Why do some banks offer much higher rates than others?
Online banks have lower operating costs than traditional banks with physical branches, so they can afford to pay higher rates on savings accounts. They pass their savings to you. All banks are competing for your deposits, so they use interest rate as a tool to attract customers. Rates also depend on what the Federal Reserve is doing with its own rates.