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 and businesses. In return, the bank pays you interest—a percentage of your balance that gets added to your account on a set schedule. The amount you earn depends on three things: how much money you have in the account, the interest rate the bank offers, and how often the bank compounds (adds) the interest.
Interest rates vary widely between banks. A large national bank might offer 0.01% annual interest, while an online bank might offer 4.5% or higher. The difference matters: on a $10,000 balance, 0.01% earns $1 per year, while 4.5% earns $450 per year. Banks set their own rates based on what the Federal Reserve does with its benchmark rate, but they are not required to pass along the full change to savers.
Key Takeaways
- Interest is calculated as a percentage of your account balance and paid to you on a schedule set by the bank, usually monthly or daily.
- The annual percentage yield (APY) tells you the real rate you will earn after compounding is factored in, and is the number to compare between banks.
- Compounding means interest earned gets added to your balance, and then you earn interest on that interest in the next period.
- Online banks typically offer higher interest rates than brick-and-mortar banks because they have lower overhead costs.
- Interest is taxable income—you will receive a 1099-INT form if you earn $10 or more in a year, and must report it on your tax return.
Annual Percentage Yield (APY) versus Annual Percentage Rate (APR)
Banks advertise two different numbers, and they mean different things. The Annual Percentage Rate (APR) is the basic interest rate without compounding factored in. The Annual Percentage Yield (APY) is the real rate you will earn after compounding happens over a full year.
For example, a bank might advertise 4.8% APR compounded daily. When you do the math with daily compounding over 12 months, the actual yield comes to about 4.92% APY. That extra 0.12% comes from earning interest on your interest. When you compare savings accounts between banks, always look at the APY, not the APR—that is the honest number.
How compounding works and why it matters
Compounding is the process of earning interest on interest. Here is how it works in practice: suppose you have $1,000 in an account with 4.8% APY compounded monthly. At the end of month one, the bank adds $4 in interest (roughly $1,000 × 4.8% ÷ 12). Your new balance is $1,004. In month two, the bank calculates interest on $1,004, not the original $1,000, so you earn slightly more. This repeats every month.
The frequency of compounding matters. Daily compounding (365 times per year) earns you more than monthly compounding (12 times per year), which earns more than annual compounding (once per year). Most online savings accounts compound daily. Some older savings accounts at traditional banks compound monthly or quarterly. Over time, especially with larger balances or higher rates, the difference adds up.
When and how the bank pays interest to your account
Banks add interest to your account on a schedule they set. Most online banks compound and credit interest daily, meaning the calculation happens every day but the money appears in your account once a month (usually on the first business day). Some banks credit interest quarterly (four times per year) or annually (once per year).
You do not have to do anything to receive the interest—it appears automatically. You can watch it accumulate by logging into your account online or checking your monthly statement. The interest stays in your account and earns interest itself in the next compounding period, unless you withdraw it.
Why interest rates change and how to monitor yours
Banks change their savings rates based on what the Federal Reserve does with its benchmark interest rate. When the Fed raises rates, banks usually raise savings rates too—though often not by the full amount. When the Fed cuts rates, banks cut savings rates quickly. This means the rate you earn today might be different in three months.
You should check your bank's current rate at least once a year, and more often if the Fed is actively changing rates. If your bank's rate falls significantly below what other banks offer, moving your money to a higher-paying account is straightforward. You can open a new account at another bank, transfer your balance, and close the old account. There is no penalty for moving your money between savings accounts at different banks.
How interest is taxed and what forms you will receive
Interest income is taxable. You must report it on your federal tax return, and possibly on your state return depending on where you live. If you earn $10 or more in interest during a calendar year, the bank will send you a Form 1099-INT by January 31 of the following year. You will receive one copy and the bank sends a copy to the IRS.
If you earn less than $10, the bank does not have to send a form, but you still owe tax on the interest. Keep your own records of interest earned if the amount is small. The interest is taxed at your ordinary income tax rate, not at a special rate. This means a high earner in a high tax bracket pays more tax on the same interest than a lower earner would.
How to find the highest-paying savings account for your situation
Comparing rates is simple because you only need to look at one number: the APY. Online banks almost always offer higher rates than traditional banks because they do not maintain physical branches. As of recent months, online savings accounts have offered rates between 4% and 5.35% APY, while many brick-and-mortar banks offer 0.01% to 0.5%.
Before opening an account, check that the bank is FDIC-insured, which means your deposits are protected up to $250,000 if the bank fails. Nearly all legitimate banks are FDIC-insured. Also read the fine print about minimum balances, withdrawal limits, and whether the rate applies to all balances or only balances above a certain amount. Some banks offer higher rates only on the first $25,000, for example.
Frequently Asked Questions
Can I lose money if interest rates fall?
No. Your account balance never goes down because of interest rate changes. If rates fall, you simply earn less interest going forward—the money you already have stays in your account. You only lose purchasing power if inflation rises faster than your interest rate, which means your money buys less over time.
What happens to my interest if I withdraw money mid-month?
This depends on the bank's rules. Most banks calculate interest based on your daily balance, so if you withdraw money on day 15 of the month, you earn interest only on the balance you held for those 15 days. Some banks use an "average daily balance" method instead. Check your account terms or call the bank to know for sure.
Is there a limit to how much interest I can earn?
No limit exists on interest earnings. You can earn as much as your balance and the interest rate allow. However, interest income above a certain threshold may trigger tax reporting requirements or affect your may be able to access for certain government programs, so consult a tax professional if you have very large balances.
Do I have to keep money in a savings account to earn interest, or can I move it?
You can move money in and out of a savings account whenever you want. Interest is calculated on whatever balance sits in the account on each day. If you withdraw half your balance mid-month, you earn interest only on the remaining half for the rest of that period. There is no penalty for withdrawals from a regular savings account.
Why do some banks offer much higher rates than others?
Online banks offer higher rates because they have lower operating costs—no physical buildings, fewer employees, lower overhead. They pass those savings to customers through higher interest rates. Traditional banks with many branches have higher costs and offer lower rates. Both are legitimate; the choice depends on whether you value in-person service or higher earnings.