Dealing with uncertain market conditions is a growing challenge for manufacturers. Changeable manufacturing systems have been suggested as a means to overcome the challenges resulting from uncertain markets. However, for changeability to acquire wide acknowledgement and implementation within industry, a clear economic justification considering the higher initial investment of such a system is needed. This paper attempts to develop an investment model comprehending the benefits of changeability, while focusing on applicability in industry. The proposed model complements a traditional Net Present Value method by evaluating the added value for changeability at either system or machine level, using a combination of Real Options approach. The model is applied in an industrial case and demonstrates an added value for changeability in both a flexible and reconfigurable manufacturing system.