Interest is money the bank pays you for letting them use your deposits

When you put money in a savings account, the bank lends that money to other customers as mortgages, car loans, and business credit lines. In exchange, the bank pays you interest—a percentage of your balance that grows over time. The rate the bank offers you is called the annual percentage yield, or APY. This is the actual amount you'll earn in a year, including the effect of compounding (which we'll explain below).

The interest you earn is real money. It deposits into your account automatically on a schedule set by the bank—usually monthly or daily. You don't have to do anything to receive it. The catch is that interest rates are low right now. A typical savings account at a large bank might pay 0.01% APY, which means you'd earn about $1 per year on a $10,000 balance. High-yield savings accounts, usually offered by online banks, currently pay between 4% and 5% APY, which would earn you $400 to $500 per year on the same $10,000.

Key Takeaways

  • The APY shown on a savings account is the actual yearly return you'll receive, already accounting for how often interest compounds.
  • Interest compounds when the bank adds earned interest back into your balance, so the next interest payment is calculated on a larger amount.
  • Daily compounding earns you slightly more than monthly or quarterly compounding because interest is calculated and added more frequently.
  • The bank's interest rate changes based on Federal Reserve decisions, so the APY you see today may be lower or higher in three months.
  • You pay no tax on interest until you withdraw it or the year ends, but you will owe income tax on all interest earned, even if it stays in the account.

How compounding turns small interest into larger returns

Compounding is the reason interest-earning accounts build wealth over time. Here's how it works: the bank calculates interest on your current balance and adds that interest to your account. The next time interest is calculated, it's based on the new, larger balance—which includes both your original deposit and the interest you've already earned. That interest earns interest, which earns more interest, and so on.

The difference between compounding schedules is real but small. If you have $10,000 earning 4.5% APY, daily compounding will earn you about $450 in a year. Monthly compounding on the same balance and rate would earn you about $447. The daily version wins because interest is calculated 30 times instead of 12, so your balance grows slightly faster. Over decades, daily compounding adds up—but over one or two years, the difference is usually less than $10.

The APY you see advertised already includes the effect of compounding. You don't calculate it yourself. The bank shows you the APY specifically so you can compare accounts fairly: a 4.5% APY account will earn you the same amount whether the bank compounds daily, weekly, or monthly.

Why interest rates change and what that means for your money

Banks set their savings rates based on the federal funds rate, which the Federal Reserve adjusts roughly eight times per year. When the Fed raises rates, banks can charge more for loans, so they can afford to pay you more interest. When the Fed lowers rates, banks pay less. This is why you might see your APY drop from 5% to 4.5% even though you haven't touched your account.

The timing varies. Large banks often change rates within days of a Fed decision. Online banks and credit unions may wait weeks or move faster, depending on their strategy. Some banks lock in a rate for a promotional period—say, 5.25% APY for the first three months—then drop it to their standard rate. Always check the terms before opening an account.

Your existing balance is never at risk when rates change. The money you've already deposited stays in your account. Only the interest rate on future deposits and future interest calculations changes. If you have $10,000 earning 4.5% and the rate drops to 4%, you still have $10,000—you'll just earn slightly less interest going forward.

The difference between APY and APR in savings accounts

You'll see two terms: APY (annual percentage yield) and APR (annual percentage rate). For savings accounts, APY is what matters. APY includes compounding; APR does not. A savings account advertised at 4.5% APY will actually earn you 4.5% in a year. A savings account advertised at 4.5% APR would earn you less because it doesn't account for compounding.

Banks are required by law to show you the APY, so that's the number you'll see most often. APR is more common for loans (mortgages, credit cards, car loans), where the bank is charging you interest rather than paying it. When comparing savings accounts, ignore APR if you see it and focus on APY.

How often interest is deposited into your account

Banks calculate and deposit interest on different schedules. The most common are daily, monthly, and quarterly. Some accounts compound daily but deposit interest only once a month—meaning the bank calculates interest every day, adds it to your balance for the next day's calculation, but you only see the money hit your account once a month.

From a practical standpoint, the deposit schedule doesn't change how much you earn—the APY already accounts for the compounding frequency. What matters is that you can see the interest appearing in your account regularly. If you never see interest deposits, contact the bank to confirm the account is working correctly. Interest should appear at least quarterly.

What happens to interest if you withdraw money before the end of the year

Interest you've already earned stays in your account when you make a withdrawal. If you withdraw $5,000 from a $10,000 balance, you keep all the interest that's been deposited so far. The interest you earn going forward is calculated on the remaining $5,000 balance.

Some savings accounts have penalties for withdrawals, but these are rare now. Most banks allow unlimited withdrawals without penalty. However, federal rules limit you to six withdrawals per month from a savings account (this rule was temporarily suspended during the pandemic but has returned). If you exceed six, the bank may charge a fee or convert your account to a checking account. Check your account terms to see what your bank's policy is.

How taxes work on savings account interest

Interest earned in a savings account is taxable income. You owe federal income tax on all interest, even if you leave it in the account. The bank will send you a Form 1099-INT in January showing how much interest you earned the previous year. You report this on your tax return.

The amount of tax you owe depends on your total income and tax bracket. If you earned $100 in interest and you're in the 22% tax bracket, you'll owe about $22 in federal tax on that interest (your actual tax may be higher or lower depending on your situation). Some states also tax interest income. You don't pay tax when the interest is deposited—you pay it when you file your return or make estimated tax payments.

If you earned less than $10 in interest during the year, the bank may not send you a Form 1099-INT, but you still owe tax on it. Keep your own records of interest earned if the amount is small.

Frequently Asked Questions

Can I lose money in a savings account because of low interest rates?

No. Your deposit is protected by the FDIC up to $250,000, and interest is always added to your balance, never subtracted. Low interest rates mean your money grows slowly, but it doesn't shrink. If inflation is high and interest rates are low, your money loses purchasing power over time—meaning you can buy less with it—but the account balance itself only goes up.

Is there a minimum balance required to earn interest?

It depends on the bank. Some accounts require a minimum balance (often $500 to $2,500) to earn the advertised APY. Others have no minimum. If your balance drops below the minimum, the bank may pay a lower rate or no interest at all. Check the account terms before opening.

Why do online banks pay higher interest than big banks?

Online banks have lower overhead costs—no physical branches, fewer employees—so they can afford to pass more of their profits to depositors as interest. Large banks have more branches and staff, which costs money, so they pay less interest to offset those expenses. Both are safe as long as they're FDIC-insured.

What's the difference between a savings account and a money market account?

Money market accounts often pay slightly higher interest than savings accounts, but they usually require a larger minimum balance and may limit withdrawals. Both are FDIC-insured and earn interest. For most people, a regular savings account is simpler. Money market accounts make sense if you have a large balance and don't need frequent access.

Does interest compound on interest I've already earned?

Yes. Once interest is added to your account, it becomes part of your balance, and the next interest calculation includes it. This is why compounding is powerful over long periods—your interest earns interest, which earns more interest. The APY you see already includes this effect.