HomeInvestingWhat Is an Annual Percentage Yield (APY)?

What Is an Annual Percentage Yield (APY)?

An annual percentage yield is an investment’s return rate over the course of a full year. Most interest rates refer to simple interest, however with an APY, the interest is compounded on a daily, monthly, or even quarterly basis. As time passes, the accumulated interest continues to grow and is added to your existing account balance.

How Does an APY Work?

APY works in relatively the same way as compound interest, since the formula is the basis for calculating the percentage yield that an account will be charged or receive in the form of dividends. When an account is subject to compounding, the interest is added on a periodic basis regardless of the changes to the original account balance at any given time. 

Unlike an annual percentage rate, the APY gives a more balanced picture of the rate of return on an investment or loan product versus the initially advertised amount.

However, when it comes to various types of investments, not all rates are created equally and there may be variations across the multiple spectrums when considering compounding periods. For instance, the annual percentage yield on a stock will be different from that of a credit card.

Calculating the Formula for APY

The formula to calculate the annual percentage yield involves dividing the number of periods by the periodic rate and adding it to the number one. However, there are some types of investments that use a different method called Euler’s number. This takes into account the original principal, interest rate and period of time.

The following is the formula for the APY:

APY = (1+R/N)n-1

  • r = period rate
  • n = number of compounding periods
  1. Divide the number of periods by the periodic rate
  2. Add the answer to an integer of one
  3. Multiply that number by the compounding periods and subtract one

How Does Compound Interest Work?

Compound interest is accumulated by a continual increase to a specific account balance that occurs over a predetermined time frame. An account with a monthly compounding rate would accrue additional interest once every 30 days, while an account with a daily compounding cycle would increase every day.

In a rate by rate comparison, an account with compound interest would be charged a higher overall amount than the same type of account that solely relies on simple interest. When basing investments on a rate of return, those with compounding interest experience much larger gains in the long run.

Fixed vs. Variable APY

Annual percentage yields, like other kinds of interest rates can be expressed in multiple ways including fixed APY and variable APY. An account with a fixed yield will incur charges at the specified rate, or provide payouts on a recurring basis such as daily, monthly, or semi-annually.

Variable rates apply to those accounts or financial instruments in a manner that changes several times over the course of a year due to market fluctuations or swings.


Annual percentage yields differ from annual percentage rates in that an APY is based on metrics that factor in compound interest, while APR uses simple interest as a baseline

Oftentimes, the annual percentage rate on a personal loan will only include the perceived cost of borrowing money. However, the annual percentage yield reveals the full cost of borrowing funds over the course of a year due to the compounding factor that occurs with products such as credit cards, personal loans, or mortgage loans.

Example of an APY

An example of an APY would be if you opened a savings account with an initial deposit of $500 dollars, featuring an interest rate of 5%, with a monthly compounding factor. After having the account for the first year, you would end up with a balance of $526 dollars, having earned you a total of $26 dollars interest.

Frequently Asked Questions

What is a Good APY?

A good APY is one that is relatively low if it applies to situations where you are having to pay based on the accrued charges and interest. If the account APY is one that you will gain from, then it may be wise to consider an account with a higher APY.

Is APY Paid Out Monthly?

Annual percentage yields are typically paid out in monthly increments. However, the percentage that you receive each month won’t be the full rate. Although the interest is received on a monthly basis, the calculation that determines your earnings is done via an annual rate.

How Does APY Work Per Month?

The way that APY works each month is by factoring in the calculation for the annual rate then dividing it by the number of months occurring in one year. For example, an account that receives a 5 percent APY, would only have essentially one-twelfth of that amount in monthly realized earnings.

What is a 7 Day APY?

A seven day yield or APY is a mathematical formula that is used when determining the rate on a money market fund. Using this type of calculation, the yield is estimated by subtracting the current daily marker from the same marker one week prior, then multiplying it by the annual yield.


Annual percentage yields have been the qualifying factor in determining the actual cost of borrowing money or making financial investments. By using this formula you will be able to assess where your funds are best utilized when looking at long term profits or losses when it comes to your annual spending.

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