The amount you earn depends on the APY, your balance, and how long the money sits there

The interest you earn on a savings account is calculated by multiplying your account balance by the annual percentage yield (APY), then dividing by 365 days. If you keep $10,000 in an account with a 4.5% APY for a full year, you earn $450. If you keep it for six months, you earn roughly $225. The catch: most banks compound interest daily or monthly, which means you earn a small amount of interest on the interest itself—but the difference is usually a few dollars per year on typical balances.

The real variable is the APY itself. A high-yield savings account might offer 4% to 5.35% APY right now, while a traditional bank savings account might offer 0.01% to 0.05%. That same $10,000 earns $400 to $535 per year in a high-yield account versus $1 to $5 in a traditional account. The APY changes when the Federal Reserve adjusts interest rates, so what you earn this month may not be what you earn next month.

Key Takeaways

  • Interest earned equals your balance multiplied by the APY, divided by 365—so a $5,000 balance at 4% APY earns about $200 per year.
  • High-yield savings accounts currently pay 4% to 5.35% APY, while traditional bank savings accounts typically pay less than 0.1% APY.
  • APY changes when the Federal Reserve adjusts rates, so your earnings will fluctuate over time.
  • Money market accounts and certificates of deposit (CDs) often pay higher rates than savings accounts, but may have withdrawal limits or lock-in periods.
  • Interest is taxed as ordinary income, so you will owe federal income tax on what you earn.

How the calculation actually works

The formula is straightforward: Annual Interest = Balance × APY. A $25,000 balance at 4.5% APY earns $1,125 per year, or about $94 per month. If you add $500 per month to the account, the calculation becomes more complex because each deposit earns interest for a different length of time, but your bank handles this automatically.

Most banks compound interest daily, which means they calculate how much you've earned each day and add it to your balance, so tomorrow's interest is calculated on today's balance plus today's interest. Over a year, daily compounding adds roughly 0.05% more than simple interest—on $10,000 at 4.5% APY, that's about $2 extra. It matters more on larger balances and higher rates, but it is not the main driver of your earnings.

Your bank sends you a 1099-INT form at tax time if you earned $10 or more in interest during the year. You report this as ordinary income on your federal tax return, which means it is taxed at your regular income tax rate, not at a lower capital gains rate.

Why APY varies so much between banks

High-yield savings accounts are offered mostly by online banks with lower overhead costs—no physical branches, fewer employees, lower rent. They pass those savings to depositors by offering higher APY. Traditional banks with branch networks have higher costs and typically offer lower rates on savings accounts because they rely on other products (credit cards, mortgages, investment services) for profit.

APY also depends on what the bank pays to borrow money. When the Federal Reserve raises its benchmark rate, banks can borrow more cheaply and compete harder for deposits by raising savings rates. When the Fed cuts rates, banks lower savings rates because they can borrow more cheaply and do not need to attract as many deposits. This is why your earnings can drop significantly when the Fed starts cutting rates.

Some banks offer promotional rates for new customers—5% APY for the first three months, for example—then drop to a lower rate. Read the terms carefully to see when the rate changes and what the ongoing rate will be.

Comparing savings accounts to other options

A money market account typically pays slightly higher APY than a savings account but limits how many withdrawals you can make per month. A certificate of deposit (CD) locks your money away for a set term—three months, one year, five years—and pays a higher rate in exchange. If you withdraw early, you pay a penalty that can wipe out several months of interest.

A high-yield savings account has no withdrawal limits and no lock-in period, so you can move the money whenever you need it. This flexibility costs you a slightly lower rate than a CD, but the difference is usually less than 1%. If you know you will not need the money for two years, a two-year CD might pay 4.8% while a high-yield savings account pays 4.5%—a difference of $75 on a $10,000 balance over two years. If you might need the money sooner, the savings account is safer because you avoid the early withdrawal penalty.

Treasury bills, bonds, and money market funds are different products with different risks and tax treatment. They are not savings accounts and should not be treated as emergency funds.

What happens when interest rates fall

When the Federal Reserve cuts rates, banks lower their savings APY within days or weeks. A high-yield account paying 5.35% might drop to 4.75%, then to 4.25% over the course of several months. Your earnings shrink proportionally. A $50,000 balance earning $2,675 per year at 5.35% APY earns only $2,125 per year at 4.25% APY—a loss of $550 annually.

This is why some people move money between banks to chase the highest rate. If your current bank drops from 4.5% to 3.5% APY and another bank is offering 4.75%, moving $50,000 saves you about $625 per year. The transfer itself is free and takes three to five business days. The tradeoff is that you lose the convenience of staying put and may lose any promotional bonus you received when you opened the account.

CDs lock in a rate for their term, so if you buy a one-year CD at 4.8% APY, you earn 4.8% for the full year even if rates fall. This is the main advantage of CDs when rates are expected to drop.

How to maximize what you earn

The simplest move is to use a high-yield savings account instead of a traditional bank savings account. The difference between 0.05% and 4.5% APY on a $10,000 balance is $449 per year. You do the same thing—deposit money, let it sit—but earn 90 times as much.

If you have money you will not need for a specific period, a CD ladder can lock in higher rates. Buy five one-year CDs with equal amounts, so one matures every year. When the first one matures, buy a new five-year CD with the proceeds. This way you always have money coming due, but most of your balance is locked into longer-term, higher-paying CDs. The tradeoff is that you cannot access the locked money without paying an early withdrawal penalty.

Keep your emergency fund in a high-yield savings account, not a CD, because you need access without penalty. Keep money you will not need for years in a CD or Treasury bond. Do not chase promotional rates by moving money constantly—the switching costs (time, lost bonuses) usually outweigh the gains.

Frequently Asked Questions

How often is interest added to my account?

Most banks compound and deposit interest monthly, though some do it daily. Daily compounding earns you slightly more because interest is calculated on a larger balance each day. Your bank's disclosure documents will state the compounding frequency. The difference is usually a few dollars per year on typical balances.

Can I lose money in a savings account?

No. Your balance cannot go down from interest alone. If you withdraw money or your bank charges a fee, your balance drops, but interest itself only adds to your account. Savings accounts are insured by the FDIC up to $250,000 per depositor per bank, so your principal is protected even if the bank fails.

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, APY is the number that matters because it shows what you actually earn. APR is used for loans and credit cards.

Will my interest rate stay the same?

No. Banks change savings rates frequently, usually within days of a Federal Reserve rate change. Your rate can go up or down depending on market conditions. Check your bank's website or your account statements to see your current rate.

Do I have to pay taxes on savings account interest?

Yes. Interest is taxed as ordinary income at your regular tax rate. Your bank sends you a 1099-INT form if you earn $10 or more in a calendar year. You report this on your federal tax return.