Simple definition
APY is what your savings actually earn in a year once compounding is counted. Compounding means you earn interest on the interest you've already been paid. Because APY includes that effect, it's slightly higher than the plain interest rate and it's the honest number for comparing savings accounts.
Why it matters
The gap between a big-bank savings account and a high-yield one is not small. On the same balance, a better APY is free money for filling out one form — no extra hours, no risk to your principal, no catch. It's one of the few places where switching costs almost nothing and pays every month.
Real-life example
You keep a $6,000 emergency fund. At a 0.05% APY it earns about $3 a year. Moved to an account paying 4.00% APY, the same $6,000 earns roughly $240. Identical money, identical access — the only difference is where it sits.
Formula
APY = (1 + rate ÷ periods)^periods − 1
Common mistakes
- Comparing an interest rate to an APY, which quietly favors whichever account quoted the smaller number.
- Leaving an emergency fund in an account paying almost nothing out of habit.
- Missing that a headline APY is promotional and drops after a few months.
- Chasing a high APY into an account with fees or a minimum balance that cancels out the gain.
Pro tips
- Compare accounts on APY, never on the interest rate.
- Check whether the rate is introductory and what it reverts to.
- Confirm the account is FDIC- or NCUA-insured before you move money.
- Read the minimum balance and monthly fee — either can erase the extra yield.
Related Money Dictionary terms
- InterestThe money a bank pays you for keeping deposits, or the money you pay a lender for borrowing — a percentage of the balance.
- Savings AccountA bank account meant for money you don't need right away, usually paying a small amount of interest on your balance.
- High-Yield Savings AccountA savings account that pays a much higher interest rate than a standard one, often offered by online banks with lower overhead.
- Certificate of Deposit (CD)A savings product where you lock money away for a fixed term in exchange for a set interest rate, paying a penalty if you withdraw early.
- Compound InterestInterest that earns interest — the engine behind long-term growth.
- APR (Annual Percentage Rate)The yearly cost of borrowing money on a loan or credit card, stated as a percentage that includes interest and certain fees.
Frequently asked questions
What's the difference between APY and APR?
APY is what you earn on money you deposit; APR is what you pay on money you borrow. APY includes compounding, and APR includes certain fees. They're built for opposite sides of the same question.
Why is APY higher than the interest rate?
Because it counts compounding. If interest is paid monthly, next month's interest is calculated on a slightly larger balance. APY rolls that effect into one yearly figure.
Can an APY change after I open the account?
On a savings account, yes — those rates are variable and move with the wider market. A certificate of deposit locks its rate for the term instead, which is the trade-off for giving up access to the money.
Knowing what APY (Annual Percentage Yield) means is knowledge — the first half. A brick gets placed when you act on it: look up the APY on the account holding your savings, then compare it to one high-yield account.
Also builds: Emergency Fund
Sources & references
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Plain-English education — not personalized legal, tax, or investment advice.