What determines how much interest your savings account earns
The amount of interest you earn depends on three things: the annual percentage yield (APY) the bank offers, how much money you have in the account, and how long it stays there. A bank with a 4.5% APY will pay you more than one offering 0.01% APY on the same balance. The difference between accounts at different banks can be hundreds of dollars per year on the same deposit.
Banks set their own APY rates based on what the Federal Reserve charges them to borrow money. When the Fed raises its rates, banks eventually raise savings rates. When the Fed cuts rates, banks cut savings rates — sometimes faster than they raised them. This means the APY you see today may not be the same six months from now.
Interest compounds, which means you earn interest on your interest. If your account compounds daily, you earn a tiny bit each day, and tomorrow you earn interest on that tiny bit plus your original balance. Accounts that compound monthly or quarterly pay less because the compounding happens less often. Most savings accounts compound daily.
Key Takeaways
- The APY posted by the bank is the rate you earn; a 4.5% APY on $10,000 earns roughly $450 per year, though the exact amount depends on how often interest compounds.
- Banks change their APY rates regularly, so the rate you lock in today may drop in three months or rise if you move your money.
- 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 than regular savings accounts, but money market accounts may have withdrawal limits and CDs lock your money away for a set period.
How to calculate interest on your own balance
The simplest way to estimate your annual interest is to multiply your account balance by the APY as a decimal. A $5,000 balance at 4.5% APY earns roughly $225 per year: $5,000 × 0.045 = $225. This is an approximation because it does not account for daily compounding, but it is close enough for planning.
For a more precise number, you need to know how often the bank compounds interest. Most banks compound daily, which means they divide the APY by 365, calculate that day's interest, add it to your balance, and repeat. After a year of daily compounding at 4.5% APY, $5,000 becomes $5,230.11 instead of $5,225. The difference is small on modest balances but grows with larger amounts.
Your bank's website or account statement should show the current APY and how often it compounds. If you cannot find it, call the bank or check the disclosure document they gave you when you opened the account.
Why savings account interest rates vary so much between banks
Online banks pay significantly more than traditional banks because they do not maintain physical branches. A brick-and-mortar bank pays rent, utilities, and staff salaries for hundreds of locations. An online bank has one or two data centers. That cost difference gets passed to customers: online banks often pay 4% to 5% APY while traditional banks pay 0.01% to 0.5% on the same type of account.
Credit unions sometimes pay higher rates than banks because they are member-owned rather than shareholder-owned. They return profits to members instead of paying dividends to investors. However, credit unions have membership requirements — you may need to live in a certain area, work for a certain employer, or belong to a certain organization.
Banks also offer different rates to different customers based on account type and balance. A premium savings account with a $25,000 minimum might pay 4.75% APY while a regular savings account pays 4.25%. Some banks offer higher rates to new customers for the first few months, then drop the rate. Read the fine print before opening an account.
How interest compounds and what that means for your money
Compounding is the process of earning interest on interest. On day one, the bank calculates interest on your balance and adds it to the account. On day two, the bank calculates interest on the new, slightly higher balance. This repeats every day for a year, and by the end, you have earned more than if the bank had straightforward paid you one lump sum at the end of the year.
The more often interest compounds, the more you earn. Daily compounding beats monthly compounding, which beats quarterly compounding. The difference is small in the first month but compounds over time. On a $10,000 balance at 4.5% APY, daily compounding earns $461.36 per year while monthly compounding earns $460.38. Over five years, daily compounding earns $2,313.55 while monthly earns $2,308.65 — a $5 difference on the same balance.
This is why the APY matters more than the interest rate. APY already includes the effect of compounding, so you can compare banks directly. If Bank A offers 4.5% APY and Bank B offers 4.5% APY, you earn the same amount regardless of how often they compound.
Comparing savings accounts, money market accounts, and CDs
A regular savings account lets you deposit and withdraw money whenever you want, with no penalty. Interest rates are lower because the bank cannot count on your money staying put. You can access your cash in one to three business days.
A money market account pays more interest than a savings account but limits how many withdrawals you can make per month — usually six. If you exceed the limit, the bank may charge a fee or close the account. Money market accounts also typically require a higher minimum balance, often $2,500 or more. Interest rates are higher because the bank has more control over when you can take your money out.
A certificate of deposit (CD) locks your money away for a set period — three months, six months, one year, five years, or longer. In exchange, the bank pays the highest interest rate of the three. If you withdraw before the term ends, you pay a penalty, usually a few months of interest. CDs are useful if you know you will not need the money for a specific amount of time.
| Account Type | Typical APY Range | Withdrawal Rules | Minimum Balance |
|---|---|---|---|
| Savings Account | 0.01% to 5% | Unlimited, no penalty | $0 to $500 |
| Money Market Account | 0.05% to 5.35% | Up to 6 per month | $2,500 to $25,000 |
| CD (1-year) | 4% to 5.5% | Locked for term; penalty to withdraw early | $500 to $2,500 |
What happens to your interest if you move your money or close the account
Interest accrues up to the day you close the account or move your money. If you close on the 15th of the month, you earn interest through the 15th. The bank pays out any accrued interest along with your principal balance. You do not lose interest by switching banks.
If you move money between your own accounts at the same bank, interest continues to accrue in the new account. The bank does not penalize you for moving money within your own accounts. However, some banks charge a fee if you move money to an external account too frequently — usually more than three to six times per month. Check your account agreement.
If you have a CD and withdraw before the term ends, you forfeit some or all of the interest you would have earned. A one-year CD with a three-month penalty means you lose three months of interest if you cash out early. The bank explains the penalty terms before you open the CD.
How inflation affects what your interest actually buys you
Interest is only useful if it outpaces inflation. If your savings account earns 1% APY but inflation is 3%, your money loses purchasing power even though the account balance grows. A dollar in your account today buys less next year if inflation is higher than your interest rate.
This is why the current environment matters. When inflation is 2% and savings accounts pay 4.5% APY, you are earning real returns — your money is actually growing in value. When inflation is 5% and savings accounts pay 4.5% APY, you are losing ground. You should compare the APY to the current inflation rate to understand whether your savings are actually growing or shrinking in real terms.
High-yield savings accounts became popular because they finally offered rates above inflation. Before 2022, most savings accounts paid less than 1% APY while inflation hovered around 2%. Now that rates have risen, high-yield accounts pay 4% to 5% APY, which is above current inflation. This situation can change if the Fed cuts rates or inflation rises again.
Frequently Asked Questions
How often does interest get added to my account?
Most banks compound and deposit interest daily, but some compound daily and deposit monthly. This means interest accrues every day but shows up in your account once a month. Check your account agreement or call the bank to confirm. The frequency of deposit does not change how much you earn — only the frequency of compounding matters.
Can a bank lower my interest rate after I open the account?
Yes. Banks can change APY rates at any time for existing accounts. They typically give you notice before the change takes effect, usually 30 days. If you do not like the new rate, you can move your money to another bank. Some banks offer promotional rates that are may provide for a set period, then drop to a lower rate.
Is my interest taxable?
Yes. Interest earned in a savings account is taxable income. The bank sends 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. High-yield savings accounts that pay 4% to 5% APY can generate significant taxable income, so factor that into your planning.
What is the difference between APY and APR?
APY (annual percentage yield) includes the effect of compounding, while APR (annual percentage rate) does not. Banks use APY for savings accounts and APR for loans. When comparing savings accounts, always look at the APY, not the interest rate, because APY tells you what you actually earn.
Do I earn interest on money I just deposited?
Interest starts accruing the day the deposit clears, not the day you make the deposit. If you deposit money on Friday and it clears on Monday, interest starts on Monday. Some banks have a grace period where they do not charge fees on new accounts for a few days, but interest accrual follows the clearing date.