What you'll earn depends on the bank's APY, how much you deposit, and how long the money sits there

The amount of interest you earn from a savings account is calculated by multiplying your account balance by the annual percentage yield (APY) the bank offers, then dividing by 12 for a monthly figure. If you have $5,000 in an account with a 4.5% APY, you earn roughly $225 per year, or about $18.75 per month. The actual amount varies because interest compounds — meaning you earn interest on your interest — and because your balance changes when you deposit or withdraw money.

The real number you'll see depends on three things: the APY your bank advertises, whether that rate is fixed or variable, and how often the bank compounds interest. Most savings accounts compound daily, which means interest gets calculated and added to your balance every single day. Some compound monthly or quarterly, which results in slightly less total interest. Banks are required to disclose their APY in writing before you open an account, so you can compare the actual earning power across different banks.

Key Takeaways

  • Your earnings equal your balance multiplied by the APY divided by 12 for a monthly estimate, though the exact amount shifts as your balance changes.
  • APY rates vary widely by bank and change over time — online banks typically offer higher rates than brick-and-mortar banks.
  • Daily compounding means you earn interest on your interest, which adds up faster than monthly or quarterly compounding.
  • Your total earnings depend on how long money stays in the account; moving money out early stops the interest clock on that portion.

How the math works with different balances and rates

The formula is straightforward: multiply your balance by the APY, then divide by 12 to get the monthly interest. A $10,000 balance at 4.5% APY earns $37.50 per month. At 5.0% APY, the same $10,000 earns $41.67 per month. The difference seems small month to month, but over a year it adds up to $50 more in your pocket.

The real impact shows up when you compare banks. If you keep $50,000 in savings, the difference between a 4.0% APY and a 5.0% APY is $500 per year. That gap widens further if you're earning on a larger balance or if rates stay different for multiple years. This is why shopping around for the highest APY matters — you're not just moving money, you're choosing how much interest the bank will pay you.

Compounding adds another layer. With daily compounding, the interest earned each day gets added to your balance, so the next day's interest is calculated on a slightly larger amount. Over a year, this compounds to roughly 5% more total interest than if the bank only compounded monthly. The difference is small on small balances but meaningful on larger ones.

Why APY rates differ between banks and change over time

Banks set their own APY rates based on what the Federal Reserve charges them to borrow money. When the Fed raises its benchmark rate, banks can afford to pay more on savings accounts because their own costs go up. When the Fed cuts rates, banks lower what they pay you. This is why savings account rates have climbed and fallen dramatically over the past few years — the Fed raised rates aggressively starting in 2022, and many online banks passed those increases directly to customers.

Online banks typically offer higher APY than traditional banks because they have lower overhead costs. They don't maintain physical branches, so they can afford to pay you more of the interest they earn. A brick-and-mortar bank might offer 0.01% APY while an online bank offers 4.5% or higher on the same type of account. The money is equally safe — both are FDIC-insured up to $250,000 — but your earnings can differ by hundreds of dollars per year.

Rates are not locked in. A bank can lower the APY on your savings account at any time, though they must notify you before doing so. Some banks raise rates frequently to stay competitive; others raise them once and leave them alone. If your bank's rate drops significantly below what competitors offer, moving your money to a higher-paying account is a straightforward way to increase your earnings.

How long your money needs to stay in the account

Interest accrues every day your money is in the account, so the longer it sits, the more you earn. If you deposit $5,000 on January 1 at 4.5% APY and leave it untouched for the full year, you earn roughly $225. If you withdraw $2,500 on July 1, you've only earned interest on $5,000 for six months and $2,500 for six months — roughly $112.50 instead of $225.

Some accounts charge fees for withdrawals or require a minimum balance to earn the advertised rate. High-yield savings accounts typically have no withdrawal limits and no minimum balance requirements, so you can move money in and out without losing the rate. Money market accounts sometimes impose limits on how many times you can withdraw per month. Check the account terms before opening to understand whether your earning rate applies to all balances and whether there are restrictions on moving money.

The difference between fixed and variable rates

Most savings accounts offer variable rates, meaning the APY can change at any time. This is actually good for you right now — if rates stay high or rise further, your earnings increase automatically without you doing anything. If rates fall, your earnings fall too, but you're not locked into a lower rate.

Some banks offer fixed-rate savings products, usually called certificates of deposit (CDs). With a CD, the bank locks in a specific APY for a set period — typically three months to five years. If you deposit $10,000 in a one-year CD at 5.0% APY, you earn exactly $500 over that year, no matter what happens to market rates. The tradeoff is that you can't withdraw the money early without paying a penalty, usually a few months' worth of interest.

What happens to interest if you close the account

Interest stops accruing the moment you close the account. If you close on the 15th of the month, you receive interest only through the 14th. The bank calculates your final balance including all accrued interest and sends it to you, usually within one to three business days. You don't lose the interest you've already earned — it's paid out as part of your closing balance.

If you're moving money to a different bank, the timing matters slightly. Interest continues to accrue in your old account until it's officially closed, and your new account starts earning from the day the deposit clears. There's usually a one to three day gap where money is in transit and not earning interest anywhere, but this gap is unavoidable and typically costs you only a few cents.

How to estimate your earnings before opening an account

Use this simple calculation: take your balance, multiply by the APY as a decimal, and divide by 12. A $25,000 balance at 4.75% APY: $25,000 × 0.0475 ÷ 12 = $99.48 per month. Most banks also provide an interest calculator on their website where you can plug in your balance and see the projected monthly and yearly earnings.

Remember that this is an estimate. Your actual earnings will be slightly higher because of daily compounding, and they'll change if your balance changes or if the bank adjusts the rate. But this calculation gives you a realistic sense of what to expect and lets you compare one bank's offer against another's before you move your money.

Frequently Asked Questions

Do I pay taxes on savings account interest?

Yes. Interest earned on 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, and you report this on your tax return. The tax you owe depends on your overall income and tax bracket, but the interest itself is always subject to federal income tax.

Will my interest rate stay the same forever?

No. Banks can change variable rates at any time, though they must notify you first. If rates drop, your earnings drop. If rates rise, your earnings rise. The only way to lock in a rate is to open a CD, which fixes the APY for a set term but prevents you from withdrawing early without a penalty.

Is it better to keep money in a savings account or a checking account?

Savings accounts earn interest; most checking accounts earn nothing or nearly nothing. If you're not using the money soon, a savings account is the better choice. If you need regular access for bills and everyday spending, a checking account is necessary, but you can keep your emergency fund or longer-term savings in a high-yield savings account at a different bank.

What if I add money to my savings account during the year?

Each deposit starts earning interest from the day it clears. If you deposit $1,000 on March 1 and another $2,000 on September 1, the first $1,000 earns interest for the full year while the second $2,000 earns interest for only four months. Your total interest is the sum of what each deposit earned over its time in the account.

Can I earn more interest by moving my money to a different bank?

Yes, if your current bank's rate is significantly lower than competitors. Moving money takes one to three days, during which it earns nothing, but if the rate difference is 1% or more, you'll make back that lost interest within a few months and come out ahead over time.