What determines how much interest your savings account earns

The amount of interest you earn depends on three things: the annual percentage yield (APY) your bank offers, how much money you have in the account, and how long it stays there. A bank sets its own APY based on what the Federal Reserve's interest rates are doing and how much competition exists in your area. You do not negotiate it—you either accept what the bank offers or move your money elsewhere.

Right now, savings account APY ranges from nearly 0% at some large national banks to 4% to 5% at online banks and credit unions, depending on the month and the institution. The difference between 0.01% and 4.5% on $10,000 is roughly $450 per year versus $1 per year. That gap matters, and it changes as Federal Reserve policy shifts.

Interest compounds, usually daily or monthly. That means you earn interest on your interest. On a $10,000 balance at 4.5% APY compounded daily, you earn about $450 in the first year, but some of that $450 itself earns interest in the months after you receive it. The effect is small on savings accounts but real over time.

Key Takeaways

  • Your bank sets the APY; it is not set by the government, and you cannot negotiate it once you open the account.
  • Online banks and credit unions typically offer 4% to 5% APY, while large national banks often offer less than 1%.
  • The APY changes when the Federal Reserve changes its rates, so the interest you earn this month may differ from next month.
  • Interest compounds daily or monthly at most banks, meaning you earn small returns on the interest itself.
  • Moving money to a higher-APY account can add hundreds of dollars per year on the same balance.

How banks decide what APY to offer

Banks use the Federal Reserve's benchmark interest rate as a starting point. When the Fed raises rates, banks can afford to pay more on savings accounts because they earn more on the loans they make. When the Fed cuts rates, banks lower what they pay you. The lag between a Fed move and a bank's response varies—some online banks react within days, while large national banks may wait weeks or never fully pass the rate cut along to customers.

Competition also drives APY. In markets where many online banks operate, rates climb because banks compete for deposits. In smaller towns with one or two banks, rates stay lower because customers have fewer options. A bank's own funding needs matter too: if a bank needs deposits urgently, it raises APY to attract them. If it has plenty of deposits already, it can afford to offer less.

How to calculate the interest you will earn

The basic formula is: (Balance × APY) ÷ 365 = Daily Interest. Multiply that daily amount by the number of days your money sits in the account, and you have your total interest earned.

Example: You have $5,000 in an account offering 4.5% APY. ($5,000 × 0.045) ÷ 365 = $0.62 per day. After 30 days, you earn roughly $18.60. After a year, you earn $225. Most banks show you the projected interest in your online dashboard, so you do not have to do this math yourself.

If your balance changes during the month—you deposit $2,000 or withdraw $1,000—the bank recalculates based on your daily balance. Some banks use the average daily balance method instead, which smooths out the ups and downs. Either way, the difference is small on typical savings account balances.

Why APY varies so much between banks

A large national bank with branches in every city has high overhead costs: rent, staff, technology, advertising. It passes some of those costs to customers by offering lower APY. An online bank with no physical locations has far lower costs and can afford to pay you more.

Credit unions often offer competitive rates because they are member-owned and do not answer to shareholders demanding profit growth. They can return earnings to members through higher rates. However, credit unions may have membership requirements (you must live or work in a certain area, or belong to a specific employer or organization) that limit who can join.

Banks also use APY as a marketing tool. A new online bank might offer 5% for three months to attract deposits, then drop to 4% once it has enough customers. Read the terms carefully to see if a promotional rate expires.

How interest rates change and what that means for you

The Federal Reserve meets roughly every six weeks to decide whether to raise, lower, or hold its benchmark rate steady. When it moves, banks adjust their savings account APY within days to weeks. You do not have to do anything—your rate updates automatically. However, the direction matters: if the Fed is cutting rates, your interest earnings will shrink even if you do nothing.

If you locked in 4.5% APY last year and rates have since dropped to 3%, you are earning more than new customers. But if rates rise to 5%, your rate stays at 4.5% unless you move your money to a new account. Banks do not retroactively raise rates on existing accounts; they only lower them. This is why checking rates periodically and switching banks when your current rate falls behind makes sense.

Rate changes also affect how much interest you earn on the same balance. A $50,000 account earning 4.5% generates $2,250 per year. If the rate drops to 2%, the same account generates $1,000 per year—a loss of $1,250 in annual income, even though you did nothing wrong.

Comparing savings accounts to find the best rate

Start by checking what your current bank offers. Go to its website or call and ask for the current APY on savings accounts. Write it down. Then visit three to five online banks—Ally, Marcus, Wealthfront, or others—and note their rates. Most publish APY prominently on their homepage because it is their main selling point.

Do not choose based on rate alone. Check whether the bank requires a minimum balance, charges monthly fees, or limits how many withdrawals you can make per month. Some banks offer slightly lower rates but waive fees or allow unlimited transfers. Read the deposit insurance information to confirm your money is covered by the FDIC (Federal Deposit Insurance Corporation) up to $250,000 per account owner per bank.

Once you find a better rate, opening a new account takes 10 to 15 minutes online. Transfer your money from your old bank using an ACH transfer (usually free and takes one to three business days) or a wire transfer (faster but may cost $15 to $30). Keep your old account open for a few days after the transfer clears to make sure nothing bounces.

When a higher APY is worth switching banks

If you have $10,000 or more, the difference between a 0.5% rate and a 4.5% rate is worth switching. That is $400 per year on $10,000. If you have $1,000, the difference is $40 per year—still real money, but smaller. For very small balances under $1,000, the difference may not justify the effort of opening a new account, though it takes only minutes.

Switching also makes sense if you are moving money anyway—say, to a different bank for checking or to consolidate accounts. Do it while you are already in the process. If your current rate has not changed in over a year and the Fed has raised rates, check what competitors offer. Rates move slowly, but they do move, and your bank is counting on inertia to keep you from noticing.

Frequently Asked Questions

Do I have to pay taxes on savings account interest?

Yes. The bank sends you a 1099-INT form each January if you earned $10 or more in interest during the year. You report that interest as income on your tax return. The interest is taxed at your ordinary income tax rate, not as a capital gain. If you earned $200 in interest and your tax bracket is 22%, you owe roughly $44 in federal tax on that interest.

Can a bank lower my APY without warning?

Yes. Banks can lower rates at any time without your permission. They usually notify you by email or mail a few days before the change takes effect, but they are not required to ask your consent. This is why checking your rate periodically matters—if it drops significantly, you can move your money to a higher-paying account.

What is the difference between APY and APR on a savings account?

APY includes the effect of compounding interest; APR does not. On a savings account, always look at APY because it shows what you actually earn. APR is used for loans and credit cards, where you pay interest rather than earn it.

Is my money safe if I move it to an online bank for a higher rate?

Yes, as long as the bank is FDIC-insured. Check the bank's website for the FDIC logo or search the FDIC's bank finder tool. Your deposits are covered up to $250,000 per account owner per bank, whether the bank has physical branches or operates only online. Online banks are not riskier than traditional banks from a safety standpoint.

How often does the interest rate on savings accounts change?

Banks can change rates whenever they want, but most move within a few days to a few weeks after the Federal Reserve changes its benchmark rate. The Fed meets roughly every six weeks. Between Fed meetings, rates usually stay stable unless a bank decides to adjust for competitive reasons. Check your bank's website or call once or twice a year to see if your rate has shifted.