What happens to your money when a bank pays interest

When you deposit money in a savings account, the bank lends that money to other customers—for mortgages, car loans, credit cards. The bank keeps the difference between what it pays you and what borrowers pay the bank. That difference is your interest rate, expressed as a percentage of your balance per year.

If your account earns 4.50% APY (annual percentage yield) and you keep $1,000 in the account for a full year without touching it, you'll earn $45 in interest. The bank adds that $45 to your account, and the next year you earn interest on $1,045. This is called compounding—you earn interest on the interest you already earned.

The rate you see advertised is what the bank promises to pay right now. Banks change rates frequently, sometimes weekly. Your rate can go up or down depending on what the Federal Reserve does and how much competition exists in your area. Some accounts lock in a rate for a set period; most savings accounts do not.

Key Takeaways

  • Banks pay you interest because they lend your deposits to other customers and keep the spread between what they pay you and what borrowers pay them.
  • APY (annual percentage yield) includes the effect of compounding, so it is always equal to or higher than the base interest rate.
  • Interest rates change based on Federal Reserve policy and bank competition, and most savings accounts have no rate lock.
  • Online banks typically offer higher rates than brick-and-mortar banks because they have lower overhead costs.
  • The frequency of compounding—daily, monthly, or quarterly—affects how much total interest you earn, though daily compounding is now standard.

How the Federal Reserve influences what your bank pays you

The Federal Reserve sets a target range for the federal funds rate, which is the rate banks charge each other for overnight loans. When the Fed raises this rate, banks have to pay more to borrow money, so they raise the rates they pay depositors to attract savings. When the Fed lowers rates, banks lower what they pay you.

This does not happen instantly. A bank might wait weeks or months after a Fed move before changing your rate. Some banks raise rates quickly to attract new deposits but cut rates slowly when the Fed moves down. There is no rule forcing banks to pass along Fed changes at all—they move at their own pace.

The federal funds rate is not the same as your savings rate. Your rate depends on the federal funds rate, the bank's own costs, how much money they need right now, and what competitors are offering. During periods when the Fed holds rates steady, you may see your bank's rate stay flat for months.

APY versus interest rate: why the difference matters

The interest rate is the percentage the bank pays on your balance. The APY (annual percentage yield) is the total return you actually get after compounding is factored in. If a bank advertises 4.50% APY, that is the real number you should use to compare accounts.

Compounding means the bank adds interest to your account at regular intervals—usually daily. Once that interest is added, you earn interest on it in the next compounding period. Over a year, this compounds into a return slightly higher than the base rate.

Example: A bank offers 4.50% APY on a $10,000 deposit with daily compounding. After one year, you have $10,450 (not $10,450.50 or $10,451, depending on the exact compounding schedule). The difference between 4.50% and a lower advertised rate is the compounding effect. Always compare APY to APY, never APY to a base rate.

Why online banks usually pay more than traditional banks

Online banks have no physical branches, no tellers, no building leases. Their overhead is a fraction of what a bank with hundreds of locations spends. They pass some of that savings to depositors by offering higher interest rates. A brick-and-mortar bank might pay 0.01% APY while an online bank pays 4.50% APY on the same type of account.

Online banks are FDIC-insured just like traditional banks, so your money is equally protected. The trade-off is that you cannot walk into a branch to deposit cash or speak to someone in person. Most online banks let you deposit checks by phone camera and transfer money electronically, which works for most people.

Credit unions also sometimes offer competitive rates, especially if you have a membership or direct deposit. Rates vary widely by credit union, so it is worth checking what yours offers before opening an online account.

How often interest is added to your account

Banks compound interest at different intervals: daily, monthly, or quarterly. Daily compounding is now standard at most online banks and many traditional banks. Monthly or quarterly compounding is less common but still exists.

The more frequently interest compounds, the more you earn. With daily compounding, interest is calculated and added to your account every day, so you start earning interest on yesterday's interest immediately. With monthly compounding, you wait 30 days before the first interest payment hits your account.

The difference is small on balances under $10,000, but it grows with larger amounts and longer time periods. A $100,000 balance earning 4.50% APY with daily compounding versus monthly compounding could mean a difference of $10 to $15 per year. When comparing accounts, check both the APY and the compounding frequency.

What happens when rates fall and your bank cuts your rate

When the Federal Reserve lowers rates, banks eventually lower what they pay depositors. You have no control over this—it is not a penalty, just how the system works. Your bank will notify you before the change takes effect, usually by email or a notice in your online account.

If you want to lock in a higher rate before it drops, some banks offer high-yield savings accounts that adjust rates daily but do not have a lock-in period. Other banks offer certificates of deposit (CDs), which lock in a rate for a fixed term (3 months, 1 year, 5 years). If rates fall, your CD rate stays the same. If rates rise, you are stuck with the lower rate until the CD matures.

There is no way to predict when rates will rise or fall. The safest approach is to keep your emergency fund in a high-yield savings account (which you can access anytime) and use CDs only for money you will not need for several years.

How to find the best rate for your situation

Start by listing what you need: Do you need to access your money quickly, or can it sit untouched for a year? Do you have $500 or $50,000? Will you add to the account regularly or leave it alone?

For money you might need soon, compare high-yield savings accounts. Check the APY, the compounding frequency, and whether there are monthly fees (most online banks charge none). For money you will not touch for 6 months to 5 years, compare CD rates and terms.

Use a rate comparison tool or visit bank websites directly. Rates change weekly, so a comparison from last month is outdated. Write down the APY and the bank name, then check again in a few days to see if it has moved. This gives you a sense of how volatile rates are in the current environment.

Frequently Asked Questions

Can my bank lower my interest rate without warning?

Banks must notify you before lowering your rate, usually by email or account notice. You have the right to close the account if you disagree. However, the bank can change rates on savings accounts at any time—there is no rate-lock protection unless you open a CD.

Is the APY I see advertised may provide?

The advertised APY is the current rate, not a may provide. Banks can change rates daily. If you open an account today at 4.50% APY, the rate could be 4.25% next week. CDs lock in a rate for their term, but savings accounts do not.

Do I pay taxes on savings account interest?

Yes. Interest earned on a savings account is taxable income. Your bank will send you a 1099-INT form at the end of the year if you earned $10 or more in interest. You report this on your tax return. The amount you owe depends on your tax bracket.

What is the difference between a savings account and a money market account?

A money market account usually pays a higher rate than a savings account but may require a larger minimum balance and limit how many withdrawals you can make per month. Savings accounts have no withdrawal limits. Both are FDIC-insured up to $250,000.

Why do some banks offer promotional rates that are higher than their regular rates?

Banks use promotional rates to attract new deposits quickly. The high rate lasts for a set period (often 3 to 12 months), then drops to the regular rate. Read the terms carefully to see when the promotional period ends and what the rate will be after.