It is best to have a detailed calculation process and accounting form for the cost calculation of plastic products.

In order to calculate the total cost and unit cost of various products, the method of collecting production expenses according to certain cost objects. The most basic cost calculation methods are: variety method, batch method and step-by-step method. The determination of cost calculation method depends on the characteristics of enterprise production and the requirements of cost management to a great extent. For example, in the case of a large number of single-step production, only the cost needs to be calculated according to the product variety, and this cost calculation method is stable as a variety method. For another example, in the case of multi-step production of single piece and small batch, because the production is organized according to the customer's order and the production batch organized by the enterprise, the product cost should be calculated according to the order or production batch. This cost calculation method is called batch method. In the case of large-scale multi-step production, it is often necessary not only to calculate the product variety, but also to call it a step-by-step method.

In addition, there are some cost calculation methods that can be combined with the basic methods. For example, use the variety method to calculate the cost. In order to simplify the cost calculation, we can divide the products into several categories to calculate the cost of each category, and then use certain distribution standards in each category to calculate the cost of products of each scale. This method is called classification. In enterprises with relatively sound quota management system, in order to strengthen the quota control of costs, the actual cost of products can also be calculated according to norm cost, which is the so-called quota method.

It should be pointed out that due to the complexity of enterprise production, in practical work, many cost calculation methods are often used simultaneously or in combination. This mainly depends on the production characteristics of the enterprise, and its goal is to correctly calculate the product cost and simplify the cost accounting.