Actual yield refers to the amount of product obtained from a chemical reaction or process, compared to the theoretical yield which is the amount of product that could be obtained in an ideal or perfect reaction. Actual yield is usually lower than the theoretical yield due to a variety of factors, such as incomplete reactions, impurities in the starting materials, or losses during the purification or isolation of the product. The actual yield is typically expressed as a percentage of the theoretical yield, known as the percent yield.