Banks pay you interest on money you deposit, and the rate they offer determines how much you earn

A savings account interest rate is the percentage of your balance that a bank pays you each year for letting them hold your money. If you have $1,000 in an account with a 4.5% annual rate, the bank calculates interest based on that percentage and adds it to your account over time. The rate is set by the bank, not by you, and it changes when the bank decides to change it—usually in response to what the Federal Reserve does with its own rates.

Interest compounds, meaning you earn money on the money you've already earned. If your account compounds daily, the bank divides your annual rate by 365, calculates interest on your current balance each day, and adds it to your account. By the end of the year, you've earned slightly more than if interest were calculated once. The more often interest compounds, the more you earn, though the difference is usually small in savings accounts.

The rate you see advertised is called the Annual Percentage Yield (APY), and it already includes the effect of compounding. This is the number to compare between banks—not the "interest rate" alone, which doesn't account for how often interest is added to your balance.

Key Takeaways

  • Banks set their own rates and change them without notice, usually following Federal Reserve decisions that affect the broader economy.
  • APY is the rate you should compare between banks because it includes how often interest compounds into your balance.
  • Interest compounds daily, weekly, or monthly depending on the bank, meaning you earn money on previously earned interest.
  • High-yield savings accounts at online banks typically offer higher rates than traditional brick-and-mortar banks because they have lower operating costs.
  • Your rate can drop at any time, so checking your bank's current APY periodically helps you decide whether to move your money.

Why rates differ between banks and account types

Banks compete for deposits by offering different rates. Online banks—those without physical branches—usually offer higher rates than traditional banks because they spend less on buildings, staff, and overhead. A brick-and-mortar bank might offer 0.01% APY on a basic savings account, while an online bank offers 4% or higher on the same type of account. Both are real rates from real banks; the difference is their business model.

Account type also matters. Money market accounts sometimes pay more than regular savings accounts. Certificates of Deposit (CDs) lock your money away for a set period—three months, one year, five years—and pay a higher rate in exchange. If you withdraw early, you pay a penalty. High-yield savings accounts are regular savings accounts that simply pay more interest; there's no catch, though the rate can drop.

The Federal Reserve's benchmark rate influences what all banks offer. When the Fed raises its rate, banks eventually raise theirs to stay competitive. When the Fed cuts rates, banks cut theirs too, sometimes faster than they raised them. This is why your rate might be 4.5% one month and 4.25% the next—the bank is responding to economic conditions, not to anything you did.

How compounding frequency affects your earnings

Compounding happens on a schedule set by the bank: daily, weekly, monthly, or quarterly. Daily compounding is most common and pays you the most, because interest gets added to your balance 365 times a year, and each addition becomes part of the balance that earns interest the next day.

The difference between daily and monthly compounding is real but small. On $10,000 at 4% APY, daily compounding earns you about $400 per year. Monthly compounding earns you about $399. The gap widens with larger balances and higher rates, but for most people, the compounding frequency matters far less than finding a bank with a competitive rate in the first place.

APY already accounts for compounding, so you don't have to do the math yourself. When a bank advertises 4.5% APY, that's what you'll earn over a year if you leave the money untouched and the rate doesn't change. The "interest rate" (sometimes called the nominal rate) is lower—maybe 4.49%—but the APY is what matters for comparing accounts.

When and how interest gets deposited to your account

Banks calculate interest daily but deposit it on different schedules. Some add it monthly, some quarterly, some annually. You can usually find this information in the account's terms or by calling the bank. The schedule doesn't change how much you earn over a year—a 4% APY is a 4% APY whether interest lands monthly or quarterly—but it does affect when you can spend or reinvest that money.

Once interest is deposited, it becomes part of your balance and earns interest itself. This is how compounding accelerates your growth over time. If you deposit $1,000 and earn $40 in interest over the first year, that $40 earns interest in year two alongside your original $1,000.

How rate changes affect your savings

Banks can lower your rate at any time without your permission. They must notify you, usually by email or mail, but they don't need your approval. If your bank drops its rate from 4.5% to 3.5%, your money stays in the account earning the new, lower rate unless you move it elsewhere.

Rate increases are rarer but do happen when the Fed raises its benchmark rate and banks compete to attract deposits. If you see your bank's rate climbing, it's usually because the Fed has been raising rates and the bank is trying to keep customers from moving their money to competitors.

This is why it's worth checking your bank's current APY every few months. If you opened an account at 4.5% and it's now 2%, you might earn significantly more by moving to a different bank. The process is usually free—you open a new account, transfer your balance, and close the old one.

The relationship between your balance and interest earned

Interest is calculated on your average daily balance or your ending daily balance, depending on the bank. Most use average daily balance, which means they add up what you had each day of the month and divide by the number of days. This method is slightly more favorable to you if your balance fluctuates.

The larger your balance, the more interest you earn in dollar terms. $10,000 at 4% earns $400 per year; $100,000 at the same rate earns $4,000. The percentage stays the same, but the dollars grow with your balance. Some banks offer tiered rates, where higher balances earn higher percentages, though this is less common now.

Taxes on savings account interest

Interest you earn is taxable income. If you earn $400 in interest during a year, you owe federal income tax on that $400 (and possibly state income tax too, depending on where you live). Banks report interest earnings to the IRS on a 1099-INT form if you earn $10 or more in a calendar year, and they send you a copy so you can include it on your tax return.

This doesn't change how much interest the bank pays you—it's just something to account for when you're calculating your actual after-tax earnings. If you're in the 24% federal tax bracket and earn $400 in interest, you'll owe about $96 in federal tax, leaving you with $304 in after-tax gain.

Frequently Asked Questions

Can a bank lower my interest rate without asking me?

Yes. Banks can change rates on savings accounts at any time. They must notify you, usually by email or mail, but they don't need your permission. If the rate drops and you want to earn more, you can move your money to a different bank with a higher rate.

What's the difference between APY and interest rate?

The interest rate is the base percentage the bank pays. APY includes the effect of compounding—how often interest gets added to your balance and starts earning interest itself. APY is always equal to or higher than the interest rate, and it's the number you should use to compare accounts between banks.

Do I have to pay taxes on savings account interest?

Yes. Interest is taxable income. If you earn $10 or more in a year, the bank reports it to the IRS on a 1099-INT form. You include this on your tax return and pay federal income tax (and possibly state tax) on the amount you earned.

How often should I check my savings account rate?

Check every few months or whenever you hear that the Federal Reserve has changed rates. If your bank's rate has dropped significantly below what competitors are offering, moving your money to a higher-paying account takes about a week and costs nothing.

Does a higher balance earn a higher interest rate?

Usually no—the percentage rate stays the same regardless of balance. Some banks offer tiered rates where larger balances earn higher percentages, but this is uncommon. The more money you have, the more interest you earn in dollars, but the percentage applied to your balance remains constant.