In order for a company to successfully achieve its growth and business, it needs to have professional management who will know how to direct the company in that direction. Poor placement and management of professional staff can lead to unwanted business results of the company which leads to loss, indebtedness and the like. Calculation is a term that represents a calculation procedure. This calculation procedure determines the price of products and services, and in particular three types of prices - cost price, purchase price and sale price. Calculations are a significant category for any business. Calculations take up most of the time when it comes to planning. During production and sales, each cost is observed in order to achieve the best possible business. Costs are also an integral part of the calculation in the store. Calculation is a very important part of management that influences the formation of the entire business. The paper will cover the topic of "Calculations in trade" in which the concept of calculations, methods and types of calculations, their purpose and application in wholesale and retail trade will be explained. An example from practice will explain the process of making a simple and complex calculation. The reason for choosing this topic is to point out the importance of proper cost allocation and calculation of companies that are the basic basis for business decisions of management, and on which depends the success of the company.