APY Calculator

Calculate Annual Percentage Yield (APY) from nominal APR and compounding frequency. Compare yields across different compounding periods and convert APY back to APR. Pure client-side, instant results.

Reverse: APY to APR

Quick Examples

About APY Calculator

This APY (Annual Percentage Yield) calculator helps you understand the true annual return of an investment or savings account based on the nominal APR (Annual Percentage Rate) and compounding frequency. Since interest compounds over time, the actual yield is always slightly higher than the stated APR. Use this tool to compare different savings accounts, CDs, and investment products to find the best real return. All calculations happen in your browser — your financial data never leaves your device.

Features

Frequently Asked Questions

What is APY and how is it different from APR?

APY (Annual Percentage Yield) is the actual annual return you earn, accounting for compounding. APR (Annual Percentage Rate) is the nominal rate before compounding. For example, 5% APR compounded monthly yields approximately 5.12% APY. The more frequent the compounding, the higher the APY compared to the APR.

What is the APY formula?

The standard APY formula is: APY = (1 + r/n)^n - 1, where r is the annual rate (APR) and n is the number of compounding periods per year. For continuous compounding, the formula is APY = e^r - 1, where e is Euler's number (~2.71828).

Why does compounding frequency matter?

Compounding frequency determines how often interest is added to your principal. More frequent compounding means interest earns interest more often, resulting in a higher effective yield. Daily compounding yields more than monthly, which yields more than annual compounding.

Can I convert APY back to APR?

Yes! Use the reverse calculator section. The formula is APR = n × ((1 + APY)^(1/n) - 1), where n is the compounding frequency. This is useful when comparing bank accounts that quote APY to find the underlying APR.