Apr 16, 2025

What is APY? A Beginner’s Guide to Annual Percentage Yield

Written by Stephen Milioti
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You know that little percentage next to your savings account that promises to grow your money? It’s not magic — it’s APY, and it’s worth understanding if you’d like your cash to work as hard as you. 

If you’ve ever wondered “what is APY?” or thought it was some alphabet soup for finance nerds, we’ve got you. Consider this your no-fluff guide to making sense of annual percentage yield and using it to your advantage. And once you get how APY works, you’ll never fall for meh interest rates again.


Looking for a high-yield savings account? MoneyLion makes it easy to compare top-rated options from trusted banking partners. Based on your preferences, you’ll get matched with accounts that offer competitive APYs, low fees, and flexible features—so you can grow your savings without the guesswork.


Let’s keep it simple: APY stands for Annual Percentage Yield — aka the amount of interest you’ll earn in a year, including compound interest. That last bit is key. It’s what sets APY apart from your average interest rate. APY is basically the real-deal reflection of how your money grows in a savings account, certificate of deposit (CD), or other interest-bearing account.

In other words, the APY meaning is all about how much extra cash you’ll pocket in a year, assuming you leave your money untouched. Want the official-sounding APY definition? It’s the percentage that tells you the total amount of interest you’ll earn over a year, factoring in how often the bank adds interest to your account. (That’s called compounding, and we’ll get to that.)

MoneyLion’s APY calculator helps you visualize how your savings will grow over time based on different annual percentage yields, allowing you to make smarter decisions about where to keep your money.

Grab your calculator — because here’s where the math gets slightly nerdy. But we’ll break it down with a formula and an easy APY example.

Here’s the basic APY formula:

APY = (1 + r/n)ⁿ – 1

Where:

r = the annual interest rate (in decimal form)

n = number of compounding periods per year

Example Time:

Let’s say you deposit $1,000 in a savings account with a 5% annual interest rate, compounded monthly. That means r is 0.05 and n is 12.

Plug it in:

APY = (1 + 0.05/12)¹² – 1

APY = (1.004167)¹² – 1

APY ≈ 0.0512, or 5.12%

Boom: your real return is 5.12%, not just 5%. That’s the magic of compounding.

That’s how to find APY — but want a shortcut? Just use an APY calculator like MoneyLion’s to gain an understanding of how much you could save over time.

Here are some main ways of distinguishing the two. 

APR (annual percentage rate)

APY (annual percentage yield)

Tells you what you’ll pay when borrowing

Tells you what you’ll earn when saving

Found on loans, credit cards, and mortgages

Found on savings accounts, CDs, and money market accounts

Lower APR = better deal

Higher APY = Better deal

👉 Learn More: What is APR?

Compound interest is where things get juicy. Instead of earning interest on just your initial deposit, you earn interest on your interest. It’s what makes how APY works so important.

The more frequently interest compounds (daily, monthly, etc.), the faster your money grows. That’s why how to calculate APY matters — because a 5% rate compounded daily will earn you more than the same rate compounded yearly.

TL;DR: Compounding = free money momentum. So don’t sleep on it.

Let’s talk about commitment issues.

  • Fixed APY: Stays the same. Think CDs or promo-rate accounts. Great for planners who hate surprises. (Example: You open a 12-month CD at 4.5% fixed APY. It stays 4.5% the whole time, no matter what the market does.)

  • Variable APY: Changes with the market. You’ll see this with high-yield savings accounts. Can go up or down. (Example: Your online savings account starts at 4.75% APY but drops to 4.3% next quarter.)

How to choose? If you’re risk-averse, go fixed. If you like the thrill of chasing top rates, variable might be your move. Just be sure to check regularly — you can always switch banks. 

A “good” APY depends on a lot of factors, like the Fed Funds rate, overall market conditions, and type of bank you’re using. Here’s a quick cheat sheet:

  • High-yield savings account: 4.0%+ is solid in today’s market

  • Traditional savings account: Low, under 0.5% at the time of writing

  • CDs: Longer terms = better rates. Look for 4.5%+ on 12-month CDs

  • Money market accounts: Often similar to savings, but with more flexibility

Tip: To find APY that works for you, skip the brick-and-mortar banks and check online options. Fintechs and credit unions tend to serve up better yields.

Here’s the deal: once you understand how to calculate APY, you’ll never fall for meh interest again. It’s not just about the number; it’s about what’s behind the number. The APY formula gives you a real view of what you’re earning, while understanding compound interest and variable vs fixed APY helps you pick the right account for your goals.

So next time you’re choosing where to park your cash, remember: don’t just ask about the rate. Ask how it’s compounding, whether it’s fixed or variable, and whether your money is doing more than just sitting pretty.

You earned that money. Time for it to return the favor.

You earn interest — usually calculated daily and paid monthly — based on your account balance and APY.

It’s the amount of interest you’ll earn on your CD over a year, including compounding. Fixed term, fixed rate.

The interest rate is the base number. APY includes compounding, giving you the true return.

About $51.16 over one year if compounded monthly. (See? That compounding adds up.)

Credit unions often list a dividend rate (simple interest) and an APY (includes compounding). APY shows your real return.


Stephen Milioti
Written by
Stephen Milioti
Stephen Milioti is a writer, editor and content strategist based in New York City. He has written for publications including The New York Times, New York Magazine, Fortune, and Bloomberg Businessweek.

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