Banks pay you interest on the money you keep in savings, calculated as a percentage of your balance

When you deposit money into a savings account, the bank uses that money to lend to other customers. In return, the bank pays you interest — a percentage of your balance that gets added to your account on a regular schedule. The interest rate varies by bank and by the type of account. A high-yield savings account at an online bank might pay 4% or 5% per year, while a traditional savings account at a brick-and-mortar bank might pay 0.01% or less.

The amount of interest you earn depends on three things: how much money is in your account, what interest rate the bank offers, and how often the bank compounds the interest (adds it back into your balance so you earn interest on the interest). A $10,000 balance earning 4% annually will grow differently than the same balance earning 0.5%, and the difference compounds over time.

Key Takeaways

  • Interest rates on savings accounts vary widely — online banks often pay 4% to 5% annually, while traditional banks may pay less than 0.1%.
  • Interest is calculated as a percentage of your account balance and is added to your account on a schedule set by the bank, usually daily or monthly.
  • Compound interest means the bank adds interest to your balance, then calculates next month's interest on the new, larger balance.
  • You can compare rates across banks using rate-tracking websites, and switching to a higher-rate account can significantly increase what you earn over time.

How the interest rate is set and what it depends on

Banks set their own interest rates based on what the Federal Reserve does with its benchmark rate. When the Fed raises rates, banks typically raise savings account rates within weeks or months. When the Fed cuts rates, banks often cut savings rates faster than they cut rates on other products. This means the rate you see today may not be the rate you see in six months.

The type of account also matters. A money market account often pays more than a basic savings account. A certificate of deposit (CD) locks your money away for a set time — three months, one year, five years — and usually pays more than a regular savings account because the bank knows it can use your money for longer. An online bank typically pays more than a branch bank because it has lower overhead costs.

The bank's own financial health and strategy also play a role. Some banks use high rates to attract new customers. Others keep rates low because they have enough deposits already. There is no single "right" rate — you have to shop around.

How interest is calculated and added to your account

Banks calculate interest using your average daily balance — the average of what you had in the account each day of the month. If you had $10,000 for 20 days and $5,000 for 10 days, your average daily balance is roughly $8,333. The bank then applies the annual interest rate to that average and divides by 12 (or by the number of days in the period, depending on the bank's method) to get the interest for that month.

Most banks compound interest daily, meaning they calculate what you owe interest on each day, add it to your balance, and then calculate the next day's interest on the new, larger balance. Some banks compound monthly or quarterly. Daily compounding is better for you because you earn interest on the interest more often.

The bank deposits the interest directly into your account. You do not have to do anything. If your account earns $5 in interest one month, your balance goes up by $5, and next month's interest is calculated on the new balance.

The difference between APY and APR in savings accounts

APY (annual percentage yield) is what banks must show you by law. It includes the effect of compound interest and tells you what you will actually earn in a year if you do not add or withdraw money. APR (annual percentage rate) is the interest rate before compounding is factored in. Banks rarely use APR for savings accounts — they use it for loans and credit cards. When you see a savings rate advertised, it is almost always the APY.

If a bank advertises 4.50% APY on a savings account, that means if you keep $10,000 in the account for a full year without touching it, you will have $10,450 at the end. The difference between APY and the simple interest rate is small in savings accounts, but it matters more the higher the rate and the longer you leave the money alone.

How to compare interest rates across banks

The easiest way to compare is to visit rate-tracking websites like Bankrate, DepositAccounts, or the FDIC's National Rates and Rate Caps page. These sites list current rates from dozens of banks, sorted by account type and rate. You can see at a glance which banks are paying the most and which are paying almost nothing.

When you compare, look at the APY, not just the rate. Make sure you are comparing the same type of account — a high-yield savings account at one bank to a high-yield savings account at another, not a regular savings account to a money market account. Check whether the rate requires a minimum balance or a direct deposit. Some banks pay high rates only on balances up to $25,000, then drop the rate on anything above that.

Also check whether the bank is FDIC-insured. This protects your money up to $250,000 if the bank fails. Nearly all banks are FDIC-insured, but it is worth confirming, especially with smaller or online-only banks.

What happens to your interest if you withdraw money early

If you withdraw money from a regular savings account, the interest you have already earned stays in your account. The bank recalculates next month's interest based on your new, lower balance. There is no penalty for withdrawing from a savings account — you can take money out whenever you want.

Certificates of deposit (CDs) are different. If you withdraw money before the CD matures, you usually pay an early withdrawal penalty. The penalty varies by bank and by the CD term — a three-month CD might charge one month of interest, while a five-year CD might charge six months of interest. The penalty is deducted from your principal, so you could end up with less than you put in if you withdraw very early.

Money market accounts sometimes have limits on how many withdrawals you can make per month without a fee. Check your account agreement to see what the rules are.

How inflation affects what your interest earnings are actually worth

Interest is only useful if it keeps pace with inflation — the rising cost of goods and services. If inflation is 3% per year and your savings account earns 2%, you are actually losing buying power. Your balance goes up in dollar terms, but it buys less than it did before.

This is why the interest rate environment matters. When the Fed raises rates, savings rates rise too, and you have a better chance of earning a rate that beats inflation. When rates are very low, savings accounts may not keep up with inflation, and you might consider other options like short-term CDs or money market funds — though those come with their own trade-offs.

For money you need to access within a year or two, a savings account or CD is still the safest choice. For money you will not need for many years, you might explore other options, but that is outside the scope of a savings account.

Frequently Asked Questions

How often do banks add interest to my account?

Most banks compound and add interest daily, though some do it monthly or quarterly. Daily compounding is better for you because you earn interest on the interest more often. Check your account agreement or ask your bank directly how often interest is posted to your account.

Can I lose money in a savings account?

No, you cannot lose the principal you deposit. The bank cannot take money out of your account. However, if inflation rises faster than your interest rate, the money's purchasing power declines — it buys less than it did before, even though the dollar amount stays the same or grows slightly.

Why do some banks pay almost no interest?

Traditional banks with physical branches have higher costs and often do not need to attract deposits aggressively, so they keep rates low. Online banks have lower overhead and use high rates to attract customers. Shopping around can make a significant difference — the difference between 0.01% and 4.50% on $10,000 is roughly $450 per year.

Does interest count as income for taxes?

Yes, interest earned in a savings account is taxable income. Banks 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 tax rate depends on your overall income and tax bracket.

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

A money market account usually pays higher interest than a savings account but may require a larger minimum balance and limit how many withdrawals you can make per month. Both are FDIC-insured up to $250,000. Choose based on whether you need frequent access to the money and how much you have to deposit.