First, find the principal of your investment. This is the amount of money you currently have invested in a particular item, such as a stock, bond, or property.
Determine how much you receive in payments from the investment over a certain period. For this example, let's figure out the annual yield on a stock that pays a quarterly dividend of ten cents a share.
Calculate your annual interest or dividend income. Suppose you bought 100 shares of stock at $10 a share. If we ignore commissions, that makes a total investment of $1,000. The quarterly dividend of 10 cents a share would earn you $10 (0.10 X 100) after three months. Multiply that by 4 to discover that you receive $40 in a year.
Divide the yearly income of $40 by the principal of $1,000 to get a decimal of .04. Multiply that decimal by 100 to find your yield, which is 4 percent in this case.