APY Calculator

What Is an APY Calculator?

An APY calculator determines the annual percentage yield of an interest-bearing account by taking both the nominal interest rate and the effect of compound interest into account. APY is useful for understanding the effective return produced over a one-year period.

This calculator can be useful when comparing savings accounts, deposit accounts and other products that quote an annual interest rate with a specified compounding schedule. Enter the stated interest rate, select the compounding frequency and the calculator will calculate the corresponding APY.

Why Use an APY Calculator?

APY can be higher than the stated nominal interest rate because interest earned during the year can itself earn additional interest. Calculating APY makes it easier to compare rates when accounts use different compounding frequencies.

How to Use the APY Calculator

Use the calculator to convert a nominal annual interest rate into its effective annual yield after compounding.

1. Enter the nominal interest rate — Enter the stated annual interest rate as a percentage, such as 5 for 5%.
2. Select the compounding frequency — Choose how many times interest is compounded during a year.
3. Calculate the APY — Select "Calculate APY" to calculate the effective annual percentage yield.
4. Review the result — The calculator displays the APY, nominal rate and selected compounding frequency.

How to Calculate APY

Annual percentage yield accounts for compound interest over a one-year period. The standard APY formula is APY = (1 + r/n)ⁿ − 1, where r is the nominal annual interest rate expressed as a decimal and n is the number of compounding periods per year.

For example, if an account has a nominal annual interest rate of 5% and compounds monthly, the nominal rate is converted to 0.05 and the number of annual compounding periods is 12. Applying these values to the formula produces an APY slightly higher than 5% because the interest is compounded throughout the year.

APY and Compound Interest

Compound interest means that previously earned interest is added to the account balance and can subsequently earn interest itself. The more frequently interest compounds, the greater the effect can be, assuming the nominal interest rate remains unchanged.

APY vs Nominal Interest Rate

The nominal interest rate does not by itself show the full effect of compounding. APY expresses the effective annual yield after compounding, making it useful when comparing accounts with different compounding schedules.

Understanding Your APY Result

The APY shown by this calculator represents the effective annual yield based on the nominal interest rate and selected compounding frequency. It assumes the rate remains unchanged for the full year and does not account for account fees, taxes, promotional rates, minimum balances or other product-specific conditions.

This calculator does not project a specific account balance or future investment value. If an account includes regular deposits, withdrawals, changing rates or fees, its actual return may differ from the calculated APY.

Frequently Asked Questions