The amount you earn depends on your balance, the interest rate, and how long the money sits there

Interest earned on a savings account is calculated by multiplying three things: how much money you have in the account, what annual percentage yield (APY) the bank is paying, and how many days that money stays in the account. A bank with a 4.5% APY will pay you more than a bank with 0.01% APY, even if you deposit the same amount. The difference between accounts can be hundreds of dollars per year on the same balance.

The actual dollar amount you earn is usually small unless your balance is large or your APY is high. On $1,000 at 0.01% APY, you earn about $0.10 per year. On $1,000 at 4.5% APY, you earn about $45 per year. Most people earn somewhere between these two, depending on which bank they use and what type of account they open.

Banks calculate interest in different ways — some daily, some monthly, some quarterly. Most modern banks compound interest daily, meaning they calculate what you owe you each day and add it to your balance, so the next day's calculation includes yesterday's interest. This compounds your earnings over time, though the effect is small on typical savings account balances.

Key Takeaways

  • Interest earned equals your balance multiplied by the APY, divided by 365 days — so a higher APY makes a real difference in dollars earned.
  • Online banks typically offer higher APY than brick-and-mortar banks because they have lower overhead costs.
  • Money market accounts and certificates of deposit (CDs) often pay more APY than regular savings accounts, but with different rules about when you can withdraw.
  • Your bank must tell you the APY before you open the account, so you can compare the actual earnings between banks.
  • Interest earned is taxable income, and your bank will send you a 1099-INT form if you earn $10 or more in a year.

How banks calculate the interest you earn

The basic formula is straightforward: balance × APY ÷ 365 = interest earned per day. If you have $5,000 in an account paying 4.5% APY, you earn about $0.62 per day ($5,000 × 0.045 ÷ 365). Over a year, that's roughly $225. If the APY drops to 1%, you earn about $50 per year on the same balance.

Most banks use daily compounding, which means they calculate interest each day and add it to your balance when ready. The next day, they calculate interest on the new, slightly higher balance. This creates a snowball effect, but on savings account balances it is tiny — the difference between daily and monthly compounding on $5,000 is usually less than a dollar per year.

Some banks calculate interest monthly or quarterly instead of daily. This matters more if you have a very large balance or a very high APY, but for most people the difference is negligible. Your bank's disclosure documents will tell you how often they compound interest.

Why APY varies so much between banks

Online banks pay higher APY than traditional banks because they do not have the cost of physical branches, tellers, or as many employees. Those savings get passed to customers as higher interest rates. A brick-and-mortar bank might pay 0.01% APY on a savings account, while an online bank pays 4.5% APY on the exact same type of account.

Interest rates also change based on what the Federal Reserve does. When the Fed raises its benchmark interest rate, banks can afford to pay more APY because they earn more on the money they lend out. When the Fed lowers rates, banks lower APY. This means the APY you see today may be different in three months or six months.

Different account types also pay different rates. A regular savings account might pay 4.5% APY, while a money market account at the same bank might pay 4.75% APY, and a one-year CD might pay 5.0% APY. The trade-off is usually flexibility — CDs lock your money away for a set time, while savings accounts let you withdraw anytime.

The difference between high-yield and regular savings accounts

A high-yield savings account is straightforward a savings account that pays a much higher APY than a regular savings account at the same bank. There is no official definition of "high-yield" — it is a marketing term. What matters is the actual APY the bank offers.

At a traditional bank, a regular savings account might pay 0.01% APY while a high-yield savings account pays 4.5% APY. On a $10,000 balance, that is the difference between earning $1 per year and earning $450 per year. The accounts work the same way — you can deposit and withdraw whenever you want — but the interest rate is dramatically different.

High-yield accounts are almost always at online banks or credit unions, not at brick-and-mortar banks. If your current bank offers a savings account paying less than 1% APY, you are likely earning far less than you could elsewhere. Comparing APY across banks takes 10 minutes and can mean hundreds of dollars per year in additional earnings.

Money market accounts and CDs earn more, but with strings attached

A money market account is a hybrid between a savings account and a checking account. It typically pays higher APY than a savings account, but limits how many withdrawals you can make per month. Some money market accounts also come with a debit card or checkbook, so you can access your money more easily than with a regular savings account.

A certificate of deposit (CD) is an account where you agree to leave your money untouched for a set period — usually three months, six months, one year, or five years. In exchange, the bank pays you a higher APY than a savings account. If you withdraw the money before the term ends, you pay a penalty, usually equal to a few months of interest.

On a $10,000 balance, a one-year CD might pay 5.0% APY while a savings account pays 4.5% APY. That is $50 more per year. But if you need the money after six months, you lose that advantage and pay a penalty. CDs make sense if you know you will not need the money for a specific period and want to lock in a may provide rate.

What happens to your interest earnings at tax time

Interest you earn on a savings account is taxable income. Your bank must send you a 1099-INT form if you earn $10 or more in interest during the year. You report this income on your tax return, and you owe income tax on it at your regular tax rate.

If you earn $200 in interest and you are in the 22% tax bracket, you owe about $44 in federal income tax on that interest. This is one reason why the actual benefit of a savings account is smaller than the interest rate suggests — some of what you earn goes to taxes. However, interest income is still better than no interest income, and high-yield accounts still beat low-yield accounts even after taxes.

If you have multiple savings accounts or earn interest from other sources, the bank adds all of it together on the 1099-INT. You do not need to do anything special — just report the total on your tax return.

How to compare interest rates between banks

To find the bank paying the highest APY, visit the websites of several banks and look for the APY listed on their savings account page. Write down the APY and any conditions — some banks pay high APY only on balances above a certain amount, or only for the first few months. Compare the actual APY, not the marketing language.

Online banks and credit unions almost always pay more than traditional banks. If you currently bank at a brick-and-mortar bank, check what an online bank is offering. The difference is often 4% or more in APY, which translates to hundreds of dollars per year on a typical balance.

Remember that APY changes frequently. The rate you see today may be lower in three months. Some banks lower their APY gradually as the Fed cuts rates, while others drop it quickly. If you move your money to a new bank for a higher rate, check back in a few months to see if the rate is still competitive.

Frequently Asked Questions

How often does the bank add interest to my account?

Most banks calculate interest daily but add it to your account monthly. This means you earn interest every single day, but you see the deposit once a month. Some banks add interest quarterly or even annually, though this is less common now. Your bank's disclosure will tell you the exact schedule.

If I withdraw money mid-month, do I lose all the interest I earned?

No. Most banks calculate interest based on the daily balance, so you earn interest on the money for the days it was in the account. If you deposit $5,000 on the first of the month and withdraw it on the 15th, you earn interest for 15 days, not zero. The interest is usually added at the end of the month.

Can I move my money to a higher-paying bank without losing interest?

Yes. Interest is credited to your account on a schedule set by the bank, usually monthly. Once it is credited, it is yours. You can transfer your balance to a new bank and keep all the interest you earned. The new bank will start paying you their APY once the money arrives.

Why do some banks pay almost no interest?

Traditional banks with physical branches have higher costs and less competitive pressure to pay high rates. They rely on customers who value convenience or personal relationships over interest earnings. Online banks have lower costs and compete directly on APY, so they pay more. If you want to earn interest, online banks are almost always the better choice.

Is the interest I earn the same every month?

No, it varies slightly based on your balance and the number of days in the month. A month with 31 days earns slightly more than a month with 28 days. If your balance changes during the month, the interest changes too. Most people see small variations month to month, usually within a few dollars.