APY Calculator
Convert APR and compounding frequency into APY.
An APY calculator converts a nominal interest rate and compounding frequency into Annual Percentage Yield (APY) - the actual annual return you'll earn after accounting for compounding. Because APY factors in how often interest is added to your balance, it's the more accurate number for comparing savings accounts, CDs, or other interest-bearing products that compound at different frequencies.
Enter the nominal (stated) interest rate and how often it compounds - daily, monthly, quarterly, or annually - to calculate the equivalent APY.
Worked Calculation Examples
| Scenario | Result | Calculation Step |
|---|---|---|
| 5% nominal rate, compounded monthly | APY ≈ 5.12% | APY = (1 + 0.05/12)^12 − 1 = (1.0041667)^12 − 1 ≈ 1.05116 − 1 = 5.12%. |
| Same 5% nominal rate, compounded daily | APY ≈ 5.13% | APY = (1 + 0.05/365)^365 − 1 ≈ 1.05127 − 1 = 5.13% - only slightly higher than monthly compounding, illustrating how the benefit of more frequent compounding shrinks quickly. |
Why APY Is Higher Than the Nominal Rate
APY is always equal to or higher than the nominal interest rate, because compounding means interest earns interest within the year. A 5% nominal rate compounded monthly produces a slightly higher APY than 5% compounded annually, because interest credited each month starts earning its own interest for the rest of the year - the more frequent the compounding, the larger this gap becomes, though the difference shrinks as compounding gets more frequent.
APY vs. APR: Two Different Purposes
APY describes the return you earn on money you deposit (savings accounts, CDs), while APR describes the cost you pay on money you borrow (loans, credit cards) - they're calculated with related but distinct methodologies, and neither is simply the other's opposite. If you need an APY to APR calculator comparison, use APR for borrowing costs and APY for deposit yields; comparing a loan's APR to a savings account's APY doesn't produce a meaningful comparison, since they measure different things for different products.
Why Banks Advertise APY Instead of Nominal Rate
Banks commonly advertise APY on savings products because it represents the more complete, comparable figure for a consumer choosing between accounts that may compound at different frequencies. Two accounts with the same nominal rate but different compounding frequencies will have different APYs, so comparing nominal rates alone can be misleading.
How to Use the APY Calculator
- Open the APY Calculator and enter the values requested in the input fields.
- Check the units, percentages, dates, or time periods before reading the answer.
- Review the instant result and adjust any value to compare another scenario.
- Use the formula, example, and FAQs below to understand how the apy calculator works.
Frequently Asked Questions
How do I calculate APY from interest rate and compounding frequency?
APY = (1 + r/n)^n - 1, where r is the nominal annual interest rate (as a decimal) and n is the number of compounding periods per year. This calculator performs that calculation automatically.
Why is APY higher than the nominal interest rate?
Because compounding means interest earns interest within the year - the more frequently interest compounds, the more it earns on itself before the year ends, producing a total annual yield higher than the simple nominal rate.
What's the difference between APY and APR?
APY measures the return earned on deposits (like savings accounts), while APR measures the cost of borrowing (like loans). They serve different purposes and aren't directly interchangeable, even though both express an annualized percentage.
Does more frequent compounding always make a big difference?
The difference exists but shrinks as compounding gets more frequent - the gap between annual and monthly compounding is much larger than the gap between monthly and daily compounding at the same nominal rate.
Why do banks advertise APY instead of the nominal rate?
APY gives a more complete, comparable picture since it already accounts for compounding frequency, making it easier to compare two accounts that might compound differently but otherwise seem similar.
Can APY change over time on my account?
Yes, for variable-rate accounts. This calculator shows the APY based on a fixed nominal rate you enter; if your account's rate changes, your actual earned APY will change accordingly.
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Last updated: September 27, 2026.