Design is described as the main factor influencing a product’s sustainability. Life cycle assessment is used to determine the environmental impact of a product during its life cycle. However, conducting an LCA requires large amounts of information that can be difficult to obtain. For this reason, together with the fact that an LCA is time-consuming, there is reason to explore the possibilities for a simplified life cycle assessment (SLCA). The aim of this paper is to investigate how an SLCA tool could be developed to support decision making in product development processes. The SLCA tool developed for product designers includes e.g. climate impact results. The tool gives the designers an understanding of where efforts to reduce the climate impact can be allocated.