The ongoing transition to digitalization will inevitably require companies to shift their manufacturing processes towards the Industry 4.0 paradigm, to remain competitive on the market. An increasing number of companies worldwide are initiating integrated 4.0 solutions, catching up with this revolution in the very concept of production processes and the dynamics among producers, suppliers and end-users. SMEs will be particularly challenged to integrate IT and automation to gain market segments in an increasingly globalised playing-field. SMEs will either seize it by identifying opportunities and risks or succumb it. Against the background that there is no such a thing as a one-size-fits-all solution on the way to Industry 4.0, the self-assessment of firm-specific starting circumstances is an essential step prior to any digital implementation. However, the analysis of a diverse pool of existing online self-assessment tools demonstrated main application fields in the context of large companies. This paper will present a methodology developed to design self-assessment tools for Industry 4.0 readiness level, in the framework of two publicly funded EU projects, targeting small-scale craftsmanship companies in the manufacturing and construction sector. The results indicate the importance to scale existing tools to the specific framework conditions of SMEs as well as valuable approaches and concrete recommendations to consider during the conceptual and design phase.