Interest in a savings account is money the bank pays you for keeping your cash deposited with them. The bank uses your deposits to fund loans and other investments, and in return, it shares a portion of that revenue with you as interest. How much you earn depends on your interest rate, how often the bank compounds that interest, and how much you keep in the account.
How Banks Calculate Your Interest
Most banks use what’s called the daily balance method. Each day, the bank takes your account balance, multiplies it by a daily interest rate (your annual rate divided by 365), and adds the result to a running tally. At the end of the month, that accumulated interest gets credited to your account. From that point forward, your new, slightly larger balance earns interest too.
This daily calculation means every dollar you deposit starts earning interest immediately, and every dollar you withdraw stops earning interest that same day. If you deposit $5,000 on a Monday and withdraw $2,000 on Wednesday, you earn interest on the full $5,000 for two days and on $3,000 for the rest of the month.
Simple Interest vs. Compound Interest
Simple interest pays you only on your original deposit. If you put $1,000 in an account earning 1% simple interest, you’d earn exactly $10 after one year, no matter what. Compound interest works differently: once you earn interest, that interest gets added to your balance, and then you earn interest on the new, larger amount. It’s interest on top of interest.
The difference looks small at first. A $1,000 deposit at 1% compounded daily grows to $1,010.05 after a year, just five cents more than simple interest. But the gap widens with higher rates and longer time horizons. At 4.5% compounded daily, that same $1,000 earns about $46.02 in a year instead of the $45.00 you’d get from simple interest. Over five or ten years, especially with regular contributions, compounding becomes a meaningful engine for growth.
Savings accounts almost always use compound interest. The compounding frequency varies: daily is the most common at online banks, while some institutions compound monthly or quarterly. Daily compounding earns slightly more than monthly, which earns slightly more than quarterly. When comparing accounts, the difference between daily and monthly compounding on the same rate is usually just a few cents per $1,000 per year, so it matters less than the rate itself.
Interest Rate vs. APY
When you shop for a savings account, you’ll see two numbers: the interest rate and the APY, or annual percentage yield. The interest rate is the base percentage the bank uses to calculate your earnings. The APY tells you what you’ll actually earn over a full year after compounding is factored in. Because compounding adds interest on top of interest, the APY is always equal to or slightly higher than the base interest rate.
This distinction matters when you’re comparing accounts. One bank might advertise a 4% interest rate while another advertises a 4% APY. They sound the same, but the account with a 4% interest rate that compounds daily would have an APY slightly above 4%, making it the better deal. Always compare APY to APY so you’re looking at the same thing. Federal regulations require banks to disclose the APY, so it should be easy to find.
How Much You Can Expect to Earn
The range of savings account rates is enormous. The national average for a standard savings account sits at just 0.38% APY. That means $10,000 in a typical bank savings account earns roughly $38 in a full year. Many large brick-and-mortar banks pay even less than that average.
High-yield savings accounts, mostly offered by online banks, pay dramatically more. The best rates currently range from about 4.00% to 5.00% APY. At 4.50% APY, that same $10,000 earns approximately $450 in a year, nearly twelve times what the national average pays. Online banks can offer these higher rates because they don’t carry the overhead costs of running physical branches.
Opening a high-yield savings account is straightforward at most online banks. Many have no minimum balance requirements and no monthly fees. The trade-off is that you won’t have access to a local branch, but transfers to and from your checking account at another bank typically take one to two business days.
When Interest Gets Credited
Even though interest may be calculated daily, banks typically credit (deposit) it into your account on a monthly cycle. Some banks credit quarterly instead. The timing matters if you’re thinking about closing an account or transferring money: if you pull your funds out a few days before interest posts, you could lose that month’s earnings. Check your bank’s schedule so you know when to expect the deposit.
You’ll see the credited interest show up as a separate line item in your transaction history. It adds directly to your available balance, and from that moment on, it’s part of the principal that earns future interest.
Taxes on Interest Income
Interest you earn in a savings account counts as taxable income. It gets taxed at your ordinary income tax rate, the same rate applied to your wages. If your bank pays you $10 or more in interest during the year, it will send you a Form 1099-INT by the end of January the following year. This same form goes to the IRS, so the agency already knows how much you earned.
Even if you earn less than $10 and don’t receive a 1099-INT, you’re still required to report the interest on your tax return. The $10 threshold only determines whether the bank has to send you the form, not whether the income is taxable. For most people, the tax impact is manageable: earning $450 in interest on a high-yield account, for example, might cost $75 to $110 in federal taxes depending on your bracket.
What Affects Your Earnings
Three factors control how much interest you earn. The first is the APY. Shopping for a competitive rate is the single biggest lever you have. The second is your balance: interest is calculated as a percentage of what you have deposited, so a higher balance produces more dollars in earnings. The third is time. Compounding rewards patience because the interest you earned last month becomes part of the balance earning interest this month.
Savings account rates are variable, meaning the bank can change them at any time. Rates tend to move in the same direction as the Federal Reserve’s benchmark rate. When the Fed raises rates, savings APYs generally climb. When the Fed cuts, they fall. You won’t be locked into a rate the way you would with a certificate of deposit, so it’s worth checking periodically to make sure your account remains competitive.