In the Polish economy entrepreneurs have the opportunity to use many tools to facilitate decision-making processes. One of them is the cost account. For the purposes of achieving the goals set by the organizations many models of cost account are used to improve the decision-making process, ensuring the efficiency of using all production factors involved in the business. This article defines the cost, defines its goals and functions as well as its significance in the process of making short and long-term decisions. Presented are the models of cost account that managers can use, taking into account the assumptions, advantages and disadvantages of each of them. On the example of the full and variable cost account was presented the usefulness of these models in estimating the valuation of inventories and the result on sales including the decision period.