What determines how much interest your savings account earns
The amount of interest you earn depends on three things: the annual percentage yield (APY) the bank offers, how much money you have in the account, and how long it stays there. A bank offering 4.5% APY on $10,000 for one year will pay you roughly $450 in interest (before any taxes). The same $10,000 at 0.01% APY earns about $1. The difference between accounts at the same bank can be hundreds of dollars per year.
Banks set their own APY rates based on what the Federal Reserve charges them to borrow money. When the Fed raises its benchmark rate, banks typically raise savings APY within weeks or months. When the Fed cuts rates, banks often lower savings APY faster than they lower it on other products. This means the rate you see today may not be the rate you see in six months.
The type of account also matters. A regular savings account usually earns less than a money market account or a certificate of deposit (CD) at the same bank. Online banks typically offer higher APY than brick-and-mortar banks because they have lower overhead costs.
Key Takeaways
- Interest earned = (your balance × APY) ÷ 12 for monthly interest, though most banks compound daily and credit monthly or quarterly.
- APY rates vary widely between banks—from under 0.01% at some traditional banks to 4% or higher at online banks, so shopping around can add hundreds of dollars per year.
- Banks change APY rates frequently and without notice, so a rate that is competitive today may not be in three months.
- Money market accounts and CDs often pay more than regular savings accounts, but money market accounts may have withdrawal limits and CDs lock your money for a set term.
How banks calculate and pay your interest
Most banks use daily compounding, meaning they calculate interest on your balance every single day and add it to your account. The interest earned each day is tiny, but it compounds—meaning you earn interest on the interest you already earned. Over a year, this adds up to the APY shown.
Interest is usually credited to your account monthly or quarterly, depending on the bank. Some banks credit it daily. You can see the exact schedule in your account agreement or by asking customer service. The timing does not change how much you earn annually, but it affects when you can spend or reinvest the money.
Banks report interest earned to the IRS on a Form 1099-INT if you earned $10 or more in a calendar year. You must report this as income on your tax return. If you have multiple accounts, the $10 threshold applies to your total interest across all accounts at that bank, not per account.
Why rates differ so much between banks
Online banks pay higher APY because they do not maintain physical branches, do not employ as many staff, and do not spend money on advertising the way large traditional banks do. They pass those savings to customers through higher rates. A bank with 500 branches nationwide has higher costs than a bank with a website and a phone line.
Large national banks often pay the lowest rates because they rely on brand recognition and convenience rather than competitive interest rates to attract deposits. They know many customers will not bother moving their money to earn an extra $200 per year. Smaller regional banks and credit unions fall somewhere in the middle.
The bank's funding needs also matter. A bank that needs deposits urgently will raise its APY to attract money. A bank with plenty of deposits may lower its rate because it does not need more. This is why rates change frequently and vary by institution.
Comparing interest across different account types
A regular savings account is the most flexible but usually pays the lowest rate. You can deposit and withdraw money anytime without penalty. APY at traditional banks often sits below 0.05%; online banks typically offer 4% to 4.5%.
A money market account usually pays more than a savings account but may limit how many times you can withdraw per month (often three to six). Some money market accounts also require a higher minimum balance. APY is typically 0.5% to 1% higher than a savings account at the same bank.
A certificate of deposit (CD) locks your money for a set term—three months, six months, one year, five years, or longer. In exchange, you get a higher APY. The longer the term, the higher the rate usually is. If you withdraw before the term ends, you pay a penalty that can wipe out all your interest and some of your principal. CD rates vary widely by term length and bank.
A high-yield savings account is a regular savings account offered by online banks that pays significantly more than traditional bank savings accounts. There are no withdrawal limits or term locks. The trade-off is that you cannot walk into a branch—all transactions happen online or by phone.
How to calculate interest on your own balance
The basic formula is: (Balance × APY) ÷ 365 × number of days. If you have $5,000 in an account paying 4% APY, you earn roughly $200 per year, or about $0.55 per day. Over 30 days, that is roughly $16.50 in interest.
Most online banking platforms show you a running estimate of how much interest you will earn this month or this year based on your current balance. This estimate updates as your balance changes. It is not a may provide—if you withdraw money, the estimate goes down. If you deposit more, it goes up.
Banks compound daily but credit interest monthly or quarterly. This means your balance grows slightly each day, but you do not see the money in your account until the bank credits it. The compounding effect is small on savings accounts but becomes meaningful over years or on very large balances.
What happens when interest rates fall
When the Federal Reserve cuts its benchmark rate, banks lower savings APY within days or weeks. Your rate may drop from 4.5% to 3.5% or lower. Banks are not required to notify you before lowering the rate, though most do send an email or letter. Check your account statements or log in to your bank's website to see your current rate.
If your rate drops and you want to lock in a higher rate, consider moving your money to a CD or switching to a bank offering a better rate. You can move money between banks without penalty—only CDs charge early withdrawal penalties. Some people keep part of their money in a high-yield savings account (for flexibility) and part in a CD ladder (for higher rates on money they will not need soon).
Rates can also rise, though this happens less often than rate cuts. When the Fed raises rates, banks eventually raise savings APY, but the increase may lag by weeks or months. If you are in a CD when rates rise, you are locked into the lower rate until the CD matures.
Frequently Asked Questions
How often do banks change savings account interest rates?
Banks can change rates anytime without notice, though most notify customers before a rate drop. Changes often happen within days of a Federal Reserve decision, but some banks wait weeks. Check your bank's website or log in to see your current rate, or call customer service to ask when the rate was last changed.
Is the interest I earn on a savings account taxed?
Yes. Interest is taxed as ordinary income at your federal tax rate plus any state or local income tax. If you earned $10 or more in interest at a bank during the year, the bank sends you a Form 1099-INT and reports it to the IRS. You must report this on your tax return even if the bank does not send the form.
Can I move my money to a different bank if the rate drops?
Yes, and there is no penalty for moving money from a savings account or money market account to another bank. You can move it online, by check, or by wire transfer. If your money is in a CD, you will pay an early withdrawal penalty if you move it before the term ends—usually a few months of interest.
What is the difference between APY and interest rate?
APY includes the effect of compounding, while a simple interest rate does not. If a bank advertises 4% APY, you earn slightly more than 4% because of daily compounding. The difference is small on savings accounts but matters when comparing rates across banks.
Should I put all my money in a CD to earn more interest?
CDs pay more than savings accounts, but your money is locked away. If you need the cash before the CD matures, you pay a penalty. Many people split their money—keeping three to six months of expenses in a high-yield savings account and putting longer-term money in CDs. This gives you both safety and higher returns.