Annual percentage yield is the percentage return you actually earn on a savings account in one year, after the bank's compounding is factored in. It is the single most important number for comparing savings products.
This article explains how annual percentage yield works, the math behind it, and the practical ways savers use APY to grow money faster.
What Annual Percentage Yield Measures
Annual percentage yield, or APY, measures the effective interest you earn on a deposit account in 12 months. It includes the impact of how frequently the bank compounds interest.
Two accounts with identical simple interest rates can have different APYs if one compounds daily and the other monthly. APY collapses the difference into one number you can compare directly.
The Formula
APY = (1 + r/n)^n − 1, where r is the nominal interest rate and n is the number of compounding periods per year.
For a HYSA quoting 4.90% interest compounded daily, the APY is around 5.02%. For the same 4.90% compounded monthly, the APY would be about 5.01%, a tiny but real difference.
APY in Practice
Walk through a $10,000 balance:
- 4.50% APY for 1 year: about $450 in interest.
- 4.50% APY for 5 years: about $2,461 in compounded interest.
- 4.50% APY for 10 years: about $5,529 in compounded interest.
The longer you leave money in, the bigger the gap between simple interest and APY-driven compounding.
APY vs APR
APR is the borrowing equivalent of APY. APR is what you pay on a loan or credit card; APY is what you earn on a deposit.
Confusingly, APR ignores compounding. A credit card with a 21% APR compounds daily, so the actual annual interest you would pay on a sustained balance is closer to 23%. APY, by contrast, already includes compounding.
Variable vs Fixed APY
Most savings products fall into one of two camps:
- Variable APY: HYSAs and money market accounts. Bank can change the APY at any time.
- Fixed APY: CDs and Treasury bills. Locked for the term.
Variable APY products move with broader interest rates. When the Federal Reserve cuts, HYSA APYs usually fall within a few weeks.
If you want to keep an eye on every account's APY at once, an app like Monarch Money shows balances and earnings across banks and brokerages in a single dashboard.
Monarch Money
Monarch Money
Monarch Money simplifies personal finance by uniting all your accounts in one place—secure, ad-free, and built for couples. 50% off your first year when you sign up via Firstcard!
Standout feature
#1 rated budgeting app (WSJ). 50% off first year via Firstcard.
Fees
$14.99/mo or $99.99/yr ($8.33/mo)
Pros
Beautiful, ad-free interface (4.9★ App Store). Best budgeting app for couples and families. Comprehensive account syncing and cash flow forecasting.
Cons
No free tier — requires paid subscription.
Building Savings With a Strong APY
Maximize APY in three steps:
- Move your emergency fund from a low-APY checking or savings account to a top HYSA.
- Set up automatic transfers from checking to savings on payday.
- Recheck the rate every 3 months and switch if your bank falls behind.
APY and Credit Building
APY grows your savings; credit history grows your credit score. Both are pieces of the same financial picture.
Firstcard's credit builder card works with any HYSA, since both run from your everyday checking account. While the HYSA earns APY, the credit builder card reports your on-time payments to all three bureaus.
Frequently Asked Questions
What is a good APY?
In 2026, an APY above 4.0% on a savings account is competitive. The top of the market is between 4.5% and 5.0%. CDs in the same period range from 4.0% to 5.5% depending on term length.
How does APY differ from interest rate?
Interest rate is the simple annual rate; APY includes the effect of compounding. APY is always equal to or higher than the interest rate, so banks must disclose APY for fair comparison.
Does APY include taxes?
No. APY is a pre-tax return. Interest is taxed as ordinary income, so your after-tax APY depends on your federal and state marginal tax rate.
Can APY drop to zero?
Variable APYs can drop very low, sometimes near zero, but rarely to exactly zero in the U.S. CDs locked at a higher APY keep paying that rate even if market rates collapse.
