What savings account interest is and how it works
Savings account 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 through mortgages, car loans, and credit cards. The bank keeps the difference between what it pays you and what it charges borrowers. That difference is how banks make money—and they share a small piece of it with you as interest.
The bank calculates your interest based on your account balance and the interest rate it offers. The rate changes depending on the bank, the type of account, and what the Federal Reserve does with its benchmark interest rate. Some banks pay more than others, even though they're all insured by the same federal system.
Interest compounds, meaning you earn interest on your interest. If you have $1,000 in an account earning 4% annually and you don't withdraw anything, after one year you'll have $1,040. The next year, you earn 4% on $1,040, not just the original $1,000. Over time, compounding makes your money grow faster than simple math suggests.
Key Takeaways
- Banks pay you interest because they use your deposits to make loans to other customers and earn money on the difference.
- Interest rates vary by bank and account type, and you can compare rates across institutions before opening an account.
- Interest compounds, meaning you earn interest on your interest, which accelerates growth over time.
- The bank reports interest you earn to the IRS on a Form 1099-INT if it exceeds $10 in a calendar year, and you must report it as income on your tax return.
How interest rates are set and why they change
The Federal Reserve sets a benchmark interest rate that influences what banks pay on savings accounts. When the Fed raises its rate, banks typically raise the rates they offer on savings accounts. When the Fed lowers its rate, savings rates usually fall. This happens because banks adjust what they're willing to pay based on what they can earn from lending.
Banks also set rates based on competition. If one bank offers 4.5% and another offers 3%, customers move their money to the higher rate. Banks in competitive markets or online-only banks often pay more than large brick-and-mortar banks because they need to attract deposits without the convenience of physical branches.
The type of account also affects the rate. A regular savings account typically pays less than a money market account or a certificate of deposit (CD), even at the same bank. CDs pay more because you agree to leave your money untouched for a set period—three months, one year, five years, or longer.
How to calculate interest on your account
Banks use different methods to calculate interest, but most use daily balance compounding. This means the bank calculates interest on your balance every single day, then adds that daily interest to your account. The next day, interest is calculated on the new, slightly higher balance.
To estimate your interest, use this formula: (Balance × Annual Interest Rate) ÷ 365 = Daily Interest. If you have $5,000 and the rate is 4%, your daily interest is roughly $0.55. Over a year, that's about $200 in interest (before compounding makes it slightly higher).
Your bank statement or online account dashboard shows the interest you've earned in each period. Most banks compound and deposit interest monthly, though some do it daily or quarterly. Check your account settings to see when your bank adds interest to your balance.
The difference between APY and interest rate
APY stands for Annual Percentage Yield. It's the total return you'll get in one year, including the effect of compounding. The interest rate (also called APR in some contexts) is the percentage the bank pays, but it doesn't account for how often interest compounds.
The difference matters when you're comparing accounts. A bank offering 4% compounded daily will give you slightly more than 4% by the end of the year because of compounding. That's where APY comes in—it shows you the real number. Banks are required to display APY on savings accounts so you can compare fairly across institutions.
For example, two banks might both advertise 4% interest, but if one compounds daily and the other compounds monthly, the daily-compounding bank will pay you a bit more. The APY will reflect that difference, so always compare APY, not just the stated rate.
Taxes on savings account interest
Interest you earn on a savings account is taxable income. The bank reports it to the IRS on a Form 1099-INT if you earn $10 or more in a calendar year. You must report this interest on your federal tax return, even if the bank doesn't send you a 1099-INT.
The tax you owe depends on your overall income and tax bracket. If you're in the 22% tax bracket and earn $200 in interest, you'll owe roughly $44 in federal income tax on that interest (plus any state income tax, depending on where you live). Some states don't tax interest income, while others do.
This is one reason high-yield savings accounts matter—if you're going to pay tax on interest anyway, you might as well earn as much interest as possible. A 0.01% rate at a big bank means almost no interest and almost no tax. A 4.5% rate at an online bank means real money, and yes, real taxes, but a much larger net gain.
Where to find current savings account rates
Savings rates change frequently, so checking rates before you open an account is worth your time. Major financial websites like Bankrate, DepositAccounts, and NerdWallet maintain lists of current rates across hundreds of banks and account types. You can filter by account type, bank size, and whether you want FDIC insurance (which all legitimate banks offer).
Your own bank's website shows what it's currently paying. If your rate is significantly lower than what other banks offer, you can move your money. There's no penalty for closing a savings account and opening one elsewhere—banks expect this and don't charge exit fees on savings accounts.
When comparing rates, look at the APY, not just the interest rate. Check whether the rate is promotional (temporary) or standard. Some banks offer high rates for the first few months to attract new customers, then drop the rate. Read the fine print to see if there's a minimum balance requirement or monthly fee that would eat into your interest.
How interest compounds over time
Compounding is powerful over long periods. If you deposit $10,000 in an account earning 4% APY and never touch it, here's roughly what you'll have:
- After 1 year: $10,400
- After 5 years: $12,167
- After 10 years: $14,802
- After 20 years: $21,911
The longer your money sits, the more compounding works in your favor. This is why starting early with savings, even small amounts, matters. A teenager who puts $5,000 in a savings account at 4% APY will have roughly $10,955 by age 65, without adding another dollar. An adult who waits until age 45 to deposit the same $5,000 will have only $5,480 by 65.
The rate matters too. At 1% APY, that same $10,000 grows to $11,046 in 10 years. At 4% APY, it grows to $14,802. The difference is $3,756—all from choosing a higher-paying account. This is why shopping for rates is worth the 15 minutes it takes.
Frequently Asked Questions
Do I have to pay taxes on savings account interest?
Yes. Interest is taxable income. If you earn $10 or more in a year, the bank reports it to the IRS on Form 1099-INT, and you report it on your tax return. Even if you earn less than $10, you should still report it. The tax you owe depends on your tax bracket.
Why do online banks pay more interest than big banks?
Online banks have lower overhead costs—no physical branches, fewer employees, cheaper real estate. They pass those savings to customers by paying higher rates on deposits. They still make money by lending out your deposits at higher rates than they pay you.
Can I lose money in a savings account?
No, not from interest rates. Your balance can't go down because of interest—it only goes up or stays the same. However, if you withdraw money, your balance decreases. FDIC insurance protects up to $250,000 per account holder per bank, so your money is safe even if the bank fails.
What's the difference between a savings account and a money market account?
Money market accounts typically pay higher interest than savings accounts, but they often require a larger minimum balance and limit how many withdrawals you can make per month. Savings accounts are more flexible but pay less. Both are FDIC insured.
Does the interest rate stay the same forever?
No. Banks can change rates whenever they want, and they usually do when the Federal Reserve changes its benchmark rate. Your rate might go up or down. Some promotional rates are may provide for a set period, then drop to the bank's standard rate. Always check your account terms.