What determines how much interest you earn

The amount of interest your savings account earns depends on three things: the interest rate the bank offers, how much money you keep in the account, and how often the bank compounds that interest. A bank offering 4.50% annual percentage yield (APY) on $10,000 will pay you roughly $450 per year, but only if the rate stays the same and you don't withdraw the money. The actual dollar amount changes if any of those three factors change.

Banks set their own rates based on what the Federal Reserve does with its benchmark rate. When the Fed raises rates, banks typically raise savings rates within days or weeks. When the Fed cuts rates, banks often cut savings rates more slowly. This means the rate you see today may not be the rate you earn six months from now.

The type of account matters too. A standard savings account usually earns less than a money market account or a certificate of deposit (CD) with the same bank. Online banks tend to offer higher rates than brick-and-mortar banks because they have lower overhead costs.

Key Takeaways

  • Interest rate, account balance, and compounding frequency all affect how much you earn, and banks can change rates without notice.
  • The annual percentage yield (APY) already includes the effect of compounding, so it is the number to compare between accounts.
  • Online banks typically offer higher rates than traditional banks, sometimes 10 to 15 times higher for the same account type.
  • Money market accounts and CDs usually pay more than savings accounts, but may require higher minimum balances or lock up your money.
  • Interest is taxable income, and you will receive a 1099-INT form if you earn $10 or more in a calendar year.

How to read and compare interest rates

Banks advertise two different numbers: the interest rate and the annual percentage yield (APY). The interest rate is the raw percentage the bank pays. The APY is what you actually earn after compounding is factored in. Always compare APY to APY, never rate to APY, because compounding can make a real difference over time.

A bank compounding interest daily will pay slightly more than one compounding monthly, even if both advertise the same rate. For example, a $10,000 balance at 4.50% APY compounded daily will earn about $450 in a year. The same $10,000 at 4.50% compounded monthly will earn slightly less because interest is calculated and added to your balance less often. The APY number already accounts for this difference, so you do not have to do the math yourself.

When you are comparing accounts, write down the APY for each one. The highest APY is the one that will earn you the most money, assuming you keep the same balance for the same length of time. Rates change frequently, so check the current rate on the bank's website before you open an account, not just the rate you saw in an advertisement.

The difference between savings accounts, money market accounts, and CDs

A savings account is the most flexible. You can deposit and withdraw money whenever you want, with no penalty. The tradeoff is that the interest rate is usually lower than other account types. As of late 2024, online savings accounts typically pay between 4.00% and 5.35% APY, while traditional bank savings accounts often pay 0.01% to 0.05%.

A money market account is a hybrid. It works like a savings account but usually requires a higher minimum balance—often $2,500 to $25,000 depending on the bank. In return, it pays a higher rate, sometimes 0.50% to 1.00% more than a regular savings account. You can still withdraw money, but the account may limit how many withdrawals you can make per month.

A certificate of deposit (CD) locks your money away for a set period—typically three months to five years. In exchange, the bank pays a higher rate. A one-year CD might pay 4.75% to 5.35% APY, while a five-year CD might pay 4.50% to 5.25%. If you withdraw the money before the CD matures, you pay an early withdrawal penalty, which can eat into or eliminate your interest earnings. CDs make sense if you know you will not need the money for a specific period.

How compounding frequency affects your earnings

Compounding means the bank adds interest to your balance, and then pays interest on that interest. The more often compounding happens, the more you earn. Daily compounding is better than monthly compounding, which is better than annual compounding.

The difference is small on small balances but grows as your balance grows. On $1,000 at 4.50% APY, the difference between daily and monthly compounding is less than $1 per year. On $100,000 at 4.50% APY, daily compounding will earn you roughly $50 to $100 more per year than monthly compounding. Most online banks compound daily, which is why they are competitive even when rates are similar.

The APY already includes the compounding effect, so you do not need to calculate it yourself. If a bank says "4.50% APY," that is the total you will earn in a year if you keep the money in the account and do not make any deposits or withdrawals.

What happens when interest rates change

Banks can change savings rates at any time, and they do not have to give you advance notice. When the Federal Reserve raises its benchmark rate, competitive online banks usually raise their savings rates within a few days. When the Fed cuts rates, banks cut savings rates more slowly—sometimes weeks or months later. This means you may earn less interest in the future than you do today.

If you lock money into a CD, the rate is fixed for the entire term. A one-year CD opened today at 5.00% will still pay 5.00% when it matures, even if rates have fallen to 3.00% by then. This is both a protection and a risk: you are protected if rates fall, but you miss out if rates rise.

For a regular savings account, your rate can change at any time. Some banks raise rates quickly to compete for deposits. Others raise rates slowly. If you want to chase the highest rate, you may need to move your money to a different bank every few months. This is legal and free to do, though you will need to open a new account and transfer the funds.

How to calculate what you will actually earn

The simplest way is to use the bank's own calculator, which most online banks provide on their website. You enter your balance, the APY, and how long you plan to keep the money, and it tells you how much interest you will earn.

If you want to do it yourself, the formula is: Interest = Balance × APY × Time. If you have $5,000 in an account paying 4.50% APY and you keep it there for one year, you earn $5,000 × 0.045 × 1 = $225. For six months, it would be $5,000 × 0.045 × 0.5 = $112.50. This assumes the balance stays the same and the rate does not change.

In real life, your balance will probably change as you deposit or withdraw money, and the rate may change. Banks calculate interest daily based on your ending balance each day, so the actual amount you earn may be slightly different from what a straightforward calculation shows. The difference is usually small—a few dollars on a typical account.

Tax treatment of savings account interest

Interest you earn on a savings account is taxable income. You must report it on your federal tax return. If you earn $10 or more in interest during a calendar year, the bank will send you a 1099-INT form by January 31 of the following year. You use this form to report the interest on your tax return.

The tax you owe depends on your overall income and tax bracket. If you are in the 22% tax bracket and earn $450 in interest, you will owe roughly $99 in federal income tax on that interest (before any deductions or credits). State income tax may explore as well, depending on where you live.

This is why the actual return on your savings account is lower than the APY suggests. If an account pays 4.50% APY and you are in the 22% tax bracket, your after-tax return is closer to 3.51%. This does not change how much the bank pays you, but it affects how much money you actually keep.

Frequently Asked Questions

Can I move my money to a different bank if the rate drops?

Yes. You can close your account and open a new one at a different bank at any time, with no penalty on a regular savings account. Moving money between banks is free and usually takes one to three business days. Many people do this to chase higher rates, though it requires opening a new account and updating any automatic deposits or transfers.

What is the difference between APR and APY?

APR (annual percentage rate) does not include compounding. APY (annual percentage yield) does. For savings accounts, always look at APY because it shows what you will actually earn. APR is used for loans and credit cards, where it works differently.

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

No. There is no cap on interest earnings. The more money you keep in the account and the higher the rate, the more you earn. Some banks do have minimum balance requirements to earn the advertised rate, so check the account terms before you open it.

Do I have to pay taxes on interest if I earn less than $10?

No. The bank only sends a 1099-INT form if you earn $10 or more. However, you are still technically required to report any interest income on your tax return, even if it is less than $10. In practice, the IRS does not pursue people for small amounts.

What happens to my interest if I withdraw money mid-year?

You earn interest only on the money that was actually in the account. If you have $10,000 for six months and then withdraw it, you earn interest on $10,000 for six months only, not for the full year. The bank calculates this daily, so you do not lose interest for the days the money was there.