Interest is money the bank pays you for letting them hold your deposits
When you put money in a savings account, the bank uses that money to lend to other customers or invest it. In return, the bank pays you interest—a percentage of your balance, calculated and added to your account on a schedule the bank sets. 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.
You do not have to do anything to earn this interest. Once your account is open and money is deposited, the interest accrues automatically. The bank calculates it, deposits it into your account, and you own it. You can withdraw it anytime, just like the rest of your balance.
Key Takeaways
- Banks calculate interest as a percentage of your account balance and add it on a schedule—usually daily, monthly, or quarterly.
- The interest rate varies by bank and changes based on what the Federal Reserve does with its benchmark rate.
- Compounding means the bank pays interest on your interest, so your balance grows faster the longer money sits in the account.
- High-yield savings accounts pay significantly more interest than traditional savings accounts at the same bank.
- You can compare rates across banks online before opening an account, and rates can change after you open one.
How the bank calculates and pays your interest
Banks use a formula based on your balance, the annual interest rate, and the compounding period. If your account compounds daily, the bank divides the annual rate by 365, calculates interest on your balance that day, and adds it to your account. The next day, it calculates interest on the new, slightly higher balance. Over a month or year, this compounding effect means you earn interest on the interest you already earned.
The schedule matters. A bank that compounds daily will pay you more than one that compounds monthly, even if both offer the same annual rate. Most savings accounts compound daily and pay out (credit) the interest monthly, meaning you see the total monthly interest hit your account on the same day each month.
You will see the interest rate written as an APY (Annual Percentage Yield). This number already includes the effect of compounding, so it tells you the true annual return. If a bank advertises 4.50% APY, that is the actual amount you will earn in a year if you leave the money untouched.
Why interest rates change and what affects yours
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 savings rates within weeks. When the Fed cuts its rate, banks cut savings rates, often faster than they raised them. This means the rate you locked in when you opened your account may be lower six months later.
Banks also compete for deposits. A bank trying to attract new customers might offer a higher rate than its competitors. Once you are a customer, that bank may lower the rate. You are not locked into the rate you saw when you opened the account—banks can change it anytime, though they must notify you in advance (usually by email or mail).
The type of account also matters. A regular savings account at a large national bank might pay 0.01% APY, while a high-yield savings account at the same bank or an online bank might pay 4.00% to 5.00% APY. The difference is real and compounds over time.
High-yield savings accounts versus traditional savings accounts
A high-yield savings account is a savings account that pays a much higher interest rate than a traditional savings account. Both are FDIC-insured (up to $250,000 per depositor, per bank), so the safety is the same. The difference is purely the rate.
Online banks and some credit unions offer high-yield accounts because they have lower overhead costs than brick-and-mortar banks. They pass those savings to customers in the form of higher rates. A traditional bank's high-yield account may pay 1.00% to 2.00% APY, while an online bank's might pay 4.50% to 5.35% APY. On a $10,000 balance, that difference means $350 to $450 more per year.
The trade-off is access. High-yield accounts usually have no physical branch, so you manage money online or by phone. Deposits and withdrawals take one to three business days instead of being when ready. If you need to move money quickly or prefer in-person banking, a traditional account may suit you better, even if you earn less interest.
What happens to interest if you withdraw money
Interest is calculated on your balance on specific days or throughout the period. If you withdraw money before the interest is credited to your account, you lose the interest on that withdrawn amount for that period. If you withdraw after interest is credited, you keep it.
For example, if your account compounds daily and you have $5,000 on Monday, the bank calculates interest on $5,000 that day. If you withdraw $2,000 on Tuesday, the interest from Monday stays in your account, but Tuesday's interest is calculated on $3,000. This is why leaving money in the account longer earns more interest—the balance is higher for more days.
Some savings accounts have withdrawal limits or penalties for frequent withdrawals, though federal rules changed in 2020 and most banks no longer enforce these. Check your account terms, but generally you can withdraw anytime without losing interest you have already earned.
How to find and compare interest rates before opening an account
Interest rates change constantly, so the rate advertised today may not be the rate you get next month. That said, you can compare current rates across banks using financial websites that track savings rates, or by visiting bank websites directly. Look for the APY, not just the interest rate, because APY includes compounding.
When comparing, check whether the rate applies to all balances or only balances above a certain amount. Some banks pay higher rates on balances over $25,000 and lower rates below that threshold. Also confirm the compounding frequency—daily compounding is better than monthly, all else equal.
Once you open an account, the bank can change the rate anytime. You are not locked in. If rates rise and your bank does not raise yours, you can move your money to a bank offering a better rate. There is no penalty for closing a savings account and moving to another bank.
Tax implications of savings account interest
Interest you earn on a savings account is taxable income. At the end of each year, the bank sends you a 1099-INT form showing how much interest you earned. You report this on your tax return, and you owe federal income tax on it (and state income tax in most states).
If you earned less than $10 in interest for the year, the bank may not send a 1099-INT, but you still owe tax on it if your total income requires you to file. Keep your own records of interest earned, especially if you have accounts at multiple banks.
The tax you owe depends on your tax bracket. If you are in the 22% federal bracket and earn $500 in interest, you owe roughly $110 in federal tax on that interest. This is why high-yield accounts matter—earning 4.50% instead of 0.01% means significantly more interest to report, but also significantly more money in your pocket after taxes.
Frequently Asked Questions
Can I lose money in a savings account if interest rates fall?
No. Your principal (the money you deposited) is protected and insured by the FDIC up to $250,000. If interest rates fall, you earn less interest going forward, but you do not lose what you already have. The interest you have already earned stays in your account.
How often should I check my interest rate to see if I should move banks?
Check rates every three to six months, especially if the Federal Reserve has changed its benchmark rate. If your bank's rate falls significantly behind competitors, moving your money takes a few days and can earn you hundreds of dollars per year on a large balance. There is no cost to switching.
What is the difference between APR and APY?
APR (Annual Percentage Rate) does not include compounding. APY (Annual Percentage Yield) does. Banks must show you the APY for savings accounts, so that is the number to use when comparing rates. APY is always equal to or higher than APR because it accounts for the interest you earn on your interest.
Do I need a minimum balance to earn interest?
Most banks pay interest on any balance, even $1. Some banks require a minimum balance (like $500 or $1,000) to earn the advertised rate, or they pay a lower rate if your balance falls below the minimum. Check your account terms before opening to see if a minimum applies.
If I move money between my own accounts, does that affect my interest?
No. Moving money from a checking account to a savings account, or between savings accounts at the same bank, does not affect interest. Interest is calculated on the balance in the savings account, regardless of where that money came from. Transfers between your own accounts are not taxable events.