What Is APY and How Is It Different From Interest Rate?

Quick Answer: The interest rate is the base percentage your deposit earns before accounting for compounding, while APY, or Annual Percentage Yield, reflects the total amount you’ll actually earn in a year including the effect of compound interest. Because APY factors in compounding, it’s almost always slightly higher than the stated interest rate on the same account, and it gives a more accurate picture of what you’ll actually earn. When comparing savings accounts, APY is generally the more useful number to look at.

The Core Difference, Explained Simply

An interest rate tells you the base rate at which your money earns interest, expressed as a simple annual percentage. It doesn’t account for how often that interest gets added back to your balance throughout the year.

APY takes that same interest rate and factors in compounding, meaning it reflects what happens when the interest you’ve already earned starts earning interest of its own. Because of this compounding effect, APY is almost always a slightly higher number than the interest rate for the same account, and it represents a more complete picture of your actual annual return.

A Worked Example

Say you deposit $10,000 into an account with a 6 percent interest rate, and interest compounds monthly.

• Using the simple interest rate alone, your balance would grow by roughly 6 percent of $10,000 over the year, adding about $600, before accounting for compounding.
• Using the APY, which reflects monthly compounding on that same 6 percent rate, the effective annual yield works out to around 6.17 percent. That difference comes entirely from interest being calculated on a slightly larger balance each month, since the interest already earned gets added in before the next month’s interest is calculated.

On $10,000, that gap between the base interest rate and the APY translates to a modest but real difference in your ending balance, purely because of how frequently the interest compounds.

Why Compounding Frequency Matters

Interest can compound at different frequencies, daily, monthly, quarterly, or annually, depending on the account. A higher compounding frequency generally results in a slightly higher APY for the same stated interest rate, since interest gets added to your balance more often, giving it more opportunities to earn interest on itself throughout the year.

The effect of compounding frequency becomes more noticeable at higher interest rates. When interest rates are very low, the difference between daily and annual compounding is often just a few dollars over several years. When rates are higher, that gap becomes more meaningful, which is part of why comparing APY, not just interest rate, matters more in a higher rate environment.

APY vs APR: A Related but Different Concept

It’s easy to confuse APY with APR, Annual Percentage Rate, since the acronyms look similar, but they answer different questions.

• APY describes how much you’ll earn on money you deposit, used for savings accounts, CDs, and money market accounts
• APR describes how much it costs you to borrow money, used for loans, mortgages, and credit cards, and it typically includes fees in addition to the base interest rate

Neither is universally “better” than the other, since they measure different things. APY matters when you’re trying to understand how much a deposit account will earn you. APR matters when you’re trying to understand the true cost of borrowing.

How to Actually Use This When Comparing Accounts

• Compare APY, not interest rate, when shopping for a savings account, since APY gives you the more complete, accurate picture of what you’ll actually earn
• Check whether the APY is fixed or variable, since a high yield savings account or money market account often has a variable APY that can change with broader interest rate conditions, while a CD typically locks in a fixed APY for its term
• Don’t assume a higher APY is always better without reading the fine print, since some accounts advertise a high APY only on a limited balance tier or for a promotional period before dropping to a lower standard rate
• Remember that APY reflects annual compounding, so an account you plan to use for a very short period may not see the full benefit of the advertised rate

Mistakes People Make With APY and Interest Rate

• Assuming APY and interest rate are the same number, when APY is almost always the higher of the two due to compounding
• Comparing accounts using interest rate instead of APY, missing the more accurate picture of actual annual earnings
• Confusing APY with APR, applying a deposit account concept to a borrowing decision or vice versa
• Ignoring whether an advertised APY is variable, being surprised when a high introductory rate drops after a promotional period
• Overlooking balance tiers or minimums required to actually earn the advertised APY, which can mean a smaller portion of a large balance earns a lower effective rate

4. FAQs

1. What does APY stand for?

APY stands for Annual Percentage Yield, the total amount of interest you’ll earn on a deposit account in one year, including the effect of compound interest.

2. Why is my account’s APY higher than its interest rate?

Because APY accounts for compounding, meaning interest you’ve already earned starts earning interest of its own throughout the year, resulting in a slightly higher effective rate than the base interest rate alone.

3. Is a higher APY always better?

Generally yes for a deposit account, but it’s worth checking whether the rate is fixed or variable, and whether it applies to your full balance or only up to a certain tier, before assuming the highest advertised APY is automatically the best choice.

4. What’s the difference between APY and APR?

APY describes how much you earn on a deposit account, factoring in compounding. APR describes how much it costs to borrow money, typically including fees, and applies to loans, mortgages, and credit cards rather than savings accounts.

5. Does compounding frequency really make a big difference?

It depends on the interest rate. At low rates, the difference between daily and annual compounding is often minor. At higher rates, more frequent compounding produces a more noticeable difference in total earnings.

6. Should I compare interest rate or APY when choosing a savings account?

APY, since it reflects your actual total annual earnings including compounding, giving a more accurate comparison between accounts than the base interest rate alone.

7. Can a bank’s APY change after I open the account?

Yes, for accounts with a variable APY, such as many high yield savings and money market accounts. A CD, by contrast, typically locks in a fixed APY for its specific term.

8. Does APY apply to loans as well as savings accounts?

No. APY specifically describes earnings on deposit accounts. The comparable concept for loans and borrowing is APR, which includes the interest rate plus other fees and costs.