Purpose: The purpose of the study is to develop an investment model which can be applied during the design of a manufacturing system, that considers DMS, FMS, and RMS. With the aim of the developed model is to give decision makers monetary basis for the added from changeability. To fulfill the purpose three research questions was created:   What methods in academia are currently used to evaluate changeable manufacturing system investments?  What methods in industry are currently used to evaluate manufacturing system investments? How can an investment model be adapted to incorporate both academia and industry preferences? Method: A single-case-study was conducted within a company that is transitioning into a more reconfigurable manufacturing system. This created an empirical framework for a practical model. In parallel with the case study a literature study was conducted to attain a theoretical framework for the study. The first research question was answered with the literature study. The second research question was answered through the case study, including document studies, interviews, and a focus group, complemented with a literature study. From the theoretical and empirical framework, research question three was answered by developing the investment model following the model creation method suggested by Mitroff et al. (1974).  Implication: The wide adoption of the reconfigurable manufacturing system has yet to be fulfilled in industry, partially hinder by finding economic motivation at the investment evaluation of such a system. The focal company and most other western companies use a net present value to evaluate investments. This approach has been proved inadequate to describe the benefits of a changeable system. Literature suggests that a real option approach could successfully describe the benefits of changeability. However, the approach has been perceived by industry to be too complex. Therefore, a model needed to have enough complexity to comprehend aspect of changeability, while still be simplistic enough gain acceptance from industry. The developed model supplements traditional NPV evaluation with a real options approach, adding scenarios to incorporate uncertainties. The study indicates that it is possible to present the monetary value of added flexibility from changeable manufacturing systems in a simplistic way.