Interest grows your balance by a percentage each year

A savings account earns interest because the bank uses your money. You deposit $1,000; the bank lends that money to other customers at a higher rate than it pays you. The difference is the bank's profit. Your cut is the interest rate — a percentage of your balance that the bank adds back to your account on a set schedule.

If your account earns 4.5% annual percentage yield (APY), the bank will add 4.5% of your balance to your account over the course of a year. On $1,000, that's $45. The actual mechanics of how often that happens — daily, monthly, quarterly — changes how much you end up with, because interest compounds.

The rate itself is set by the bank and changes based on what the Federal Reserve does with its benchmark rate. When the Fed raises rates, banks raise what they pay on savings. When the Fed cuts rates, banks cut what they pay. This is why the same account might earn 4.5% one month and 4.0% three months later.

Key Takeaways

  • Interest is a percentage of your account balance that the bank adds back to your account; the rate is set by the bank and changes when Federal Reserve policy changes.
  • Compounding means interest earns interest, so an account that compounds daily will grow faster than one that compounds monthly, even at the same stated rate.
  • APY (annual percentage yield) is the rate you should compare between banks because it already accounts for how often interest compounds.
  • The interest rate on a savings account is separate from the rate on a checking account; savings accounts almost always pay more because you agree not to withdraw the money as often.

How compounding changes what you actually earn

Interest doesn't just sit there. When the bank adds interest to your account, that new balance itself earns interest in the next period. This is compounding, and it's why the frequency matters.

Say you have $10,000 at 4.8% APY. If the bank compounds annually, you get $480 at the end of the year, leaving you with $10,480. If it compounds daily, the bank divides the annual rate by 365 (roughly 0.0131% per day), calculates interest on your balance each day, and adds it back. By the end of the year, you have $10,492 — $12 more, because each day's interest earned interest the next day.

The difference grows larger with bigger balances and longer time periods. On $100,000 at the same rate, daily compounding nets you about $120 more than annual compounding over a year. Over five years, the gap widens to several hundred dollars.

This is why APY matters more than the stated interest rate. APY already includes the effect of compounding, so when you compare two accounts, APY tells you which one actually pays more. A savings account advertising "4.8% APY" will earn you more than one advertising "4.75% APY," regardless of how often each one compounds.

When interest posts to your account

Banks compound interest on different schedules. Some do it daily, some monthly, some quarterly. The schedule doesn't change how much you earn over a full year — that's what APY accounts for — but it does change when you see the money appear in your account.

Most online banks compound and post interest daily. That means every single day, the bank calculates interest on your current balance and adds it to your account. You see the balance grow a tiny bit each day. Traditional banks often compound daily but post monthly, so you don't see the interest appear until the end of the month, even though it's been accruing the whole time.

A few accounts still compound quarterly or even annually, though this is less common now. The posting schedule doesn't matter much for your long-term earnings — you'll end up with the same amount either way — but it does affect how quickly you can move that interest elsewhere if you withdraw it.

How the Federal Reserve rate affects what your bank pays

Your bank doesn't set its savings rate in a vacuum. The Federal Reserve sets a benchmark rate — currently a range between 5.25% and 5.50% — that influences what banks charge each other for short-term loans. Banks use this as a reference point when deciding what to pay depositors.

When the Fed raises its benchmark rate, banks have more incentive to attract deposits, so they raise what they pay on savings accounts. When the Fed cuts rates, banks cut what they pay. The lag is usually a few weeks to a few months. A rate cut announced in December might not show up in your account until January or February.

This is why a savings account that paid 5.0% last year might pay 4.5% now. The Fed cut rates, and your bank followed. You didn't do anything wrong; the market changed. If you're unhappy with the new rate, you can move your money to a bank offering a higher rate — there's no penalty for moving savings between banks.

The difference between savings and checking account interest

Savings accounts pay interest; most checking accounts don't, or pay almost nothing. The reason is regulatory. The Federal Reserve has rules about how often you can withdraw from a savings account — historically, no more than six times per month, though this rule is now more flexible. In exchange for limiting your access, the bank pays you interest.

Checking accounts have no withdrawal limit, so banks don't pay interest on them. They make money on checking accounts through overdraft fees and other charges, not by paying you. Some banks offer "high-yield checking" accounts that do pay interest, but these usually require a very high minimum balance or direct deposit, and the rate is still lower than savings.

If you're keeping money you don't need to touch regularly, a savings account earns you money. If you need to access your funds frequently, a checking account is the right tool, even though it doesn't pay interest.

Why different banks pay different rates on the same type of account

Two banks might both offer savings accounts, but one pays 4.5% APY and the other pays 3.8%. Both are responding to the same Federal Reserve rate, so why the difference?

Online banks typically pay more than brick-and-mortar banks because they have lower overhead. They don't maintain physical branches, so they can pass savings on to depositors in the form of higher interest rates. A bank with one branch in a small town might pay less because its costs are higher relative to the deposits it takes in.

Banks also compete for deposits differently. Some prioritize attracting new customers and offer high rates on savings accounts to do it. Others focus on loan products and don't care much about deposit rates. A bank that makes most of its money from mortgages might pay less on savings because it doesn't need deposits as urgently.

This is why it's worth comparing rates across several banks before you open an account. The difference between 4.5% and 3.8% on $50,000 is $350 per year — real money that compounds over time.

What happens to your interest if you withdraw money early

Interest accrues daily on your current balance. If you deposit $5,000 on the first of the month and withdraw $2,000 on the fifteenth, the bank calculates interest only on the balance you actually held each day. You earn interest on $5,000 for 14 days, then on $3,000 for the remaining days of the month.

There's no penalty for withdrawing from a regular savings account, and you don't lose the interest you've already earned. The bank won't claw back the $20 you earned in the first two weeks just because you withdrew money later. You keep what you've earned; you straightforward stop earning interest on the amount you withdrew.

Some accounts, like certificates of deposit (CDs), do penalize early withdrawal. A CD pays a higher rate in exchange for locking your money away for a set period — six months, one year, five years. If you withdraw before the term ends, the bank deducts an early withdrawal penalty from your balance. A regular savings account has no such penalty.

Frequently Asked Questions

Does the interest rate on my savings account ever go down automatically?

Yes. When the Federal Reserve cuts its benchmark rate, banks lower what they pay on savings accounts within weeks or months. You don't have to do anything; the rate just changes. If you want to keep earning a higher rate, you'll need to move your money to a bank that's still paying more.

Can I lose money if interest rates fall?

No. Your balance never shrinks because of a rate cut. You straightforward earn less interest going forward. If you have $10,000 and the rate drops from 4.5% to 4.0%, you'll earn $400 per year instead of $450, but you still have your $10,000.

What's the difference between APY and the interest rate?

The interest rate is the percentage the bank pays per year. APY is that rate plus the effect of compounding. If a bank compounds daily, the APY will be slightly higher than the stated rate. When comparing accounts, always use APY, because it shows you what you'll actually earn.

Do I pay taxes on savings account interest?

Yes. Interest is taxable income. The bank will send you a 1099-INT form at the end of the year if you earned more than $10 in interest, and you'll report it on your tax return. The interest counts as ordinary income, taxed at your regular rate.

Is there a limit to how much interest I can earn?

No. You can earn as much interest as your balance and the interest rate allow. There's no cap on how much a savings account can grow through interest alone. The FDIC insures up to $250,000 per account, but that's a protection against bank failure, not a limit on earnings.