This spreadsheet presents, through an example, how to make a decision about producing or buying ready-made items from third parties from the perspective of costs and contribution margin. In this example, we evaluate a situation in which any manufacturer may find itself: a situation of deciding whether to produce an item or buy it from a supplier that offers the ready-made component at a certain price - below the internal production cost. The problem that is established is based on a factory that produces its products and components and dominates the fixed and variable costs. The proposal to outsource the production of components is evaluated from the perspective of costs and contribution margin. 100 components and 100 products are produced. The components are part of the product. The company has an Indirect Production Cost of R$20,000, variable costs of R$50 per component and R$150 per product. The production of a component consumes 0.5 machine hours while the production of a product consumes 2 machine hours, so that the 100 units of components and products consume 250 machine hours. The product is sold for R$300.
 Note: The spreadsheets available for download are based on references from blog posts and should be viewed only as supplementary study material. We do not offer support for technical questions regarding the theoretical content of the spreadsheets. This material does not exempt the user from adequate monitoring by a professional in order to obtain greater reliability, both in execution and in calculations.