What you'll earn depends on the bank, the account type, and the current rate environment

The amount of interest you earn on a savings account is determined by 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 will pay you roughly 4.5% of your balance per year, but only if rates don't change. A bank offering 0.01% APY will pay you almost nothing. The difference between these two is not a rounding error—it's the difference between earning $450 per year on $10,000 or earning $1 per year on the same amount.

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 eventually raise savings rates. When the Fed cuts rates, banks cut savings rates—sometimes faster than they raised them. This means the rate you see today may not be the rate you earn six months from now.

The type of account also matters. A regular savings account typically earns less than a money market account or a certificate of deposit (CD) with the same bank. Online banks almost always pay more than brick-and-mortar banks because they have lower overhead costs.

Key Takeaways

  • The interest you earn equals your account balance multiplied by the APY, divided by 365 days—so a $10,000 balance at 4.5% APY earns roughly $450 per year, or about $1.23 per day.
  • APY rates vary widely between banks and account types; online banks typically pay 4% to 5% while traditional banks may pay 0.01% to 0.5% on the same type of account.
  • Your rate can change at any time because banks adjust APY when the Federal Reserve changes its benchmark rate, which happens several times per year.
  • Interest compounds daily at most banks, meaning you earn interest on your interest, but the effect is small unless your balance is large or the rate is high.
  • You will owe federal income tax on all interest earned, and some states tax it as well; the bank will report it to the IRS on a 1099-INT form.

How to calculate what you'll actually earn

The basic formula is simple: multiply your balance by the APY, then divide by 365. If you have $10,000 at 4.5% APY, you earn roughly $450 per year. That's $37.50 per month or $1.23 per day.

Most banks compound interest daily, which means they calculate what you owe you every single day and add it to your balance. This sounds powerful, but the effect is tiny. On $10,000 at 4.5% APY, daily compounding adds about $2.27 per year compared to annual compounding. It matters more when your balance is larger or the rate is higher, but it's not the main lever.

The real variable is the APY itself. A $10,000 balance at 0.5% APY earns $50 per year. The same balance at 4.5% APY earns $450 per year. That $400 difference is why shopping around between banks is worth an hour of your time.

Why rates differ so much between banks

Online banks pay more because they don't maintain physical branches, don't employ tellers, and don't spend money on advertising the way traditional banks do. They pass those savings to depositors in the form of higher APY. A bank like Ally or Marcus may offer 4.35% APY on a savings account while your local bank offers 0.05% on the same product. Both are legitimate; they simply have different cost structures.

Banks also compete for deposits differently. Some large banks rely on brand recognition and convenience and don't need to offer competitive rates. Smaller or newer online banks use high rates as their main tool to attract deposits. If you have $50,000 to deposit, you have leverage—you can shop around and move your money to whoever pays the most.

Account type also creates variation. A CD typically pays more than a savings account because you agree to lock your money away for a set period (three months, one year, five years, etc.). A money market account may pay more than a savings account but less than a CD. Regular savings accounts pay the least because you can withdraw anytime.

What happens when the Federal Reserve changes rates

The Federal Reserve sets a benchmark interest rate that influences what banks charge each other to borrow overnight. When the Fed raises this rate, banks eventually raise the rates they pay on savings accounts—but not always by the same amount, and not always right away. When the Fed cuts rates, banks cut savings rates, often faster than they raised them.

If you lock money into a CD, your rate is fixed for the entire term, so Fed changes don't affect you. If you keep money in a savings account or money market account, your rate can change at any time. Banks are not required to notify you before lowering your rate, though most do send an email or letter.

This is why the APY you see advertised today may not be the APY you earn next year. If you're comparing banks, look at the current rate, but also think about whether rates are likely to rise or fall. If the Fed is cutting rates, locking money into a CD now protects you from future cuts. If the Fed is raising rates, keeping money in a flexible savings account lets you benefit from future increases.

How to find the highest-paying accounts

Use a rate-comparison site like Bankrate, DepositAccounts, or NerdWallet to see what different banks are currently offering. These sites update daily and let you filter by account type, minimum balance, and whether you want FDIC insurance (you do). You can also visit banks' websites directly, though this is slower if you're comparing more than two or three.

Pay attention to the minimum balance requirement. Some banks offer high rates only if you maintain $25,000 or more. Others have no minimum. If you have $5,000, a bank requiring $25,000 minimum won't help you. Read the fine print about whether the rate applies to your entire balance or only to balances above a certain threshold.

Once you've found a bank with a good rate, open the account online (takes 10 to 15 minutes) and transfer money from your current bank. The transfer usually takes one to three business days. You don't have to close your old account right away; you can leave it open and move money gradually, or close it once the transfer clears.

Tax on savings account interest

All interest you earn is taxable income. The bank will send you a 1099-INT form by January 31 each year showing how much interest you earned. You must report this on your federal tax return, and you'll owe federal income tax on it at your marginal tax rate. If you earned $450 in interest and you're in the 22% tax bracket, you owe roughly $99 in federal tax on that interest.

Some states also tax savings account interest as income. A few states (like Illinois and Mississippi) exempt interest income entirely. Most states tax it like any other income. Check your state's tax rules or ask a tax professional if you're unsure.

This is why the actual money you keep is less than the interest earned. If you earn $450 in interest and owe $99 in tax, you keep $351. This doesn't change the math of shopping for higher rates—a higher rate still leaves you with more money after tax—but it's worth knowing that the full APY is not the full amount you pocket.

When a CD makes more sense than a savings account

A CD locks your money away for a set term (three months to five years) in exchange for a higher rate. If you know you won't need the money for that period, a CD often pays 0.25% to 0.75% more than a savings account at the same bank. On $10,000, that difference is $25 to $75 per year—not huge, but real.

The tradeoff is access. If you withdraw money from a CD before the term ends, you pay a penalty, usually equal to a few months of interest. If you might need the money, a savings account is safer. If you're certain you won't touch it, a CD locks in a rate that won't change, which is valuable if you think rates are about to fall.

Some people use a "CD ladder" strategy: buy multiple CDs with different maturity dates (one matures in one year, one in two years, one in three years, etc.). As each one matures, you can reinvest it at the current rate or withdraw the money. This gives you some flexibility while still capturing higher CD rates.

Frequently Asked Questions

Will my interest rate stay the same forever?

No. Banks can change the APY on savings accounts and money market accounts at any time. CDs have a fixed rate for the entire term, so your rate won't change until the CD matures. If you want to lock in a rate, a CD is your only option.

How often is interest added to my account?

Most banks compound interest daily, meaning they calculate and add interest every day. Some compound monthly or quarterly. Daily compounding pays slightly more, but the difference is small unless your balance is very large. Check your bank's disclosure to see how often they compound.

Can I move my money to a higher-paying bank without losing interest?

Yes. When you transfer money to a new bank, you don't lose any interest you've already earned. The old bank pays you interest through the day you withdraw, and the new bank starts paying interest the day the money arrives. There's no gap or penalty for switching banks.

What's the difference between APY and APR?

APY (annual percentage yield) includes the effect of compounding, while APR (annual percentage rate) does not. For savings accounts, banks advertise APY, which is the number that matters. APR is used for loans and credit cards. Always compare APY to APY when shopping for savings accounts.

Is my money safe if the bank fails?

Yes, as long as your balance is under $250,000 and the bank is FDIC-insured. The FDIC (Federal Deposit Insurance Corporation) guarantees your deposits up to $250,000 per account type per bank. Almost all banks are FDIC-insured; check the bank's website or the FDIC's bank search tool to confirm.