The interest rate tells you what percentage of your balance the bank will pay you each year
Your savings account interest rate is shown as an Annual Percentage Yield (APY), and it tells you exactly how much money the bank will add to your account over one year. If your APY is 4.50%, a $10,000 balance will earn $450 in interest over 12 months—though the bank usually deposits that interest monthly or daily, not all at once.
The rate your bank advertises is the one you use to calculate. You do not need to hunt for a hidden rate or adjust for inflation. The number on your account statement or the bank's website is the actual rate being applied to your money right now.
Interest rates on savings accounts change. Banks raise them or lower them based on what the Federal Reserve does with its benchmark rate. Your current rate may not be the rate you had six months ago, and it will not necessarily be the rate next quarter. Check your statement or log into your account to see what you are earning today.
Key Takeaways
- The APY shown by your bank is the annual rate; divide it by 12 to find the monthly interest, or by 365 to find the daily rate.
- Banks compound interest daily, weekly, or monthly depending on the account, which means you earn interest on interest—the more frequent the compounding, the more you make.
- To calculate total interest earned over a specific period, multiply your balance by the APY, then multiply by the fraction of the year that has passed.
- Your actual interest payment may be slightly lower than your calculation because most banks round down and some deduct fees that reduce your balance.
- Interest rates change frequently, so the rate you see today may be different next month; check your statement to confirm what you are actually earning.
How to do the basic calculation yourself
The simplest formula is: Balance × APY ÷ 12 = Monthly Interest. If you have $5,000 in the account and the APY is 4.50%, you multiply $5,000 by 0.045 (which is 4.50% written as a decimal), then divide by 12. That gives you $18.75 in interest per month.
For a full year with no deposits or withdrawals, just multiply your balance by the APY: $5,000 × 0.045 = $225 per year. That $225 is the interest the bank will pay you over 12 months.
If you want to know how much interest you will earn over a specific number of days—say, from now until you withdraw the money—use this: Balance × APY × (Days ÷ 365) = Interest Earned. If you keep $5,000 in the account for 90 days at 4.50% APY, you calculate $5,000 × 0.045 × (90 ÷ 365), which equals $55.48.
Why your actual interest may differ from your calculation
Banks compound interest, which means they add the interest you earned to your balance, and then the next time they calculate interest, they pay you interest on that interest too. This happens daily, weekly, or monthly depending on the bank. The more often interest compounds, the more total interest you earn—but the difference is usually small on a savings account.
Your balance also changes if you make deposits or withdrawals. If you deposit $2,000 midway through the month, the bank recalculates your interest based on the new, higher balance for the remaining days. If you withdraw money, your interest drops. Banks track this by calculating interest on your average daily balance or your ending balance each day, depending on their policy.
Some banks charge monthly maintenance fees that reduce your balance and therefore reduce the interest you earn. A $5 monthly fee means you are earning interest on $4,995 instead of $5,000. Read your account agreement to see whether your account has fees and when they are charged.
Where to find your current APY and interest earned
Log into your online banking account and look for the account details or account summary page. Most banks display the current APY prominently, along with the total interest you have earned so far this year or this month. If you cannot find it online, call the bank's customer service line or visit a branch with your account number.
Your monthly or quarterly statement also shows the interest deposited into your account during that period. Add up the interest deposits from each month to see your year-to-date total. This is the actual interest you earned, accounting for compounding, balance changes, and any fees.
If the interest shown on your statement does not match your calculation, the difference is usually due to compounding (which adds a small amount) or a fee you did not account for. Banks are required to disclose the APY and how often they compound, so if something looks wrong, ask the bank to explain the calculation.
How APY differs from the stated interest rate
Banks sometimes show two numbers: an interest rate and an APY. The interest rate is the base percentage, and the APY is the rate after compounding is factored in. For most savings accounts, the difference is tiny—less than 0.01%—but APY is always the number you should use for your calculations because it reflects what you actually earn.
For example, a bank might advertise a 4.48% interest rate compounded daily, which results in a 4.50% APY. The daily compounding adds that extra 0.02%. When you calculate how much interest you will earn, use the 4.50% APY, not the 4.48% rate.
Comparing interest rates between banks
Always compare APY, not the base interest rate. Two banks might advertise similar rates, but one compounds daily and one compounds monthly, so the APY will be slightly different. The bank with the higher APY is paying you more, even if the advertised rate looks the same.
A difference of 0.25% APY sounds small, but on a $10,000 balance it means $25 per year. On $50,000, it means $125 per year. Over time, especially if you keep money in savings for years, the difference adds up. Check the APY on your current account and compare it to what other banks are offering. If your bank's rate has dropped significantly, moving your money to a higher-paying account may be worth the effort.
Keep in mind that high-yield savings accounts at online banks often pay more than savings accounts at traditional brick-and-mortar banks. The trade-off is that you cannot walk into a branch to deposit cash or speak to someone in person, but the interest you earn is real money in your account.
What happens when interest rates change
When the Federal Reserve raises or lowers its benchmark rate, banks adjust the APY on savings accounts within days or weeks. Your bank will notify you of the change, usually by email or through your online account. The new rate applies to interest earned going forward; it does not change the interest you already earned.
If rates are rising, your APY will increase and you will earn more interest on the same balance. If rates are falling, your APY will decrease. Some banks lower rates faster than they raise them, so it is worth shopping around if you notice your rate has dropped significantly compared to competitors.
Frequently Asked Questions
How often does the bank add interest to my account?
Most banks deposit interest monthly, though some do it daily or quarterly. Check your account statement or contact your bank to confirm the schedule. Even if interest is calculated daily, it may only be deposited once a month, so you will not see the money in your account until then.
If I withdraw money mid-month, do I lose all the interest for that month?
No. Banks calculate interest based on your daily balance, so you earn interest on the money you had in the account for the days you held it. If you withdraw $2,000 on the 15th, you earn interest on the full balance for the first 14 days, then on the lower balance for the remaining days of the month.
Can I use an online calculator instead of doing the math myself?
Yes. Most banks provide a savings calculator on their website where you enter your balance, APY, and time period, and it shows you the interest earned. This accounts for compounding automatically and is faster than doing it by hand. Your bank's calculator is reliable because it uses the same method the bank uses to calculate your actual interest.
What if my bank shows a different interest amount than my calculation?
The difference is usually due to daily compounding (which adds a small amount), a fee you did not account for, or a change in your balance during the month. Request an explanation from your bank with the dates and amounts involved, and they can show you exactly how they arrived at the number.
Is the interest I earn on a savings account taxable?
Yes. Interest earned on a savings account is taxable income. Your bank will send you a 1099-INT form at the end of the year showing how much interest you earned, and you report that on your tax return. This is separate from calculating how much interest you earn; it is about what you owe in taxes on that interest.