Purpose: The objective of the research is proposed a methodology to prepare a Zero-Based Budget (ZBB) for Small and Medium-sized Enterprises (SMEs) in Ecuador, applying fuzzy logic. Design/methodology/approach: A quantitative approach is assumed to show findings derived from the work carried out in these Ecuadorian business units, belonging to non-essential sectors such as wood, textiles and footwear. Fuzzy logic, the technique of expertise, and Trapezoidal Fuzzy Numbers (TpFN) are used to capture true budget levels. Findings: The results recommend that optimal budget levels can be obtained for SMEs in restrictive and health emergency contexts. Originality/value: As a result of COVID-19 pandemic, markets and demand are contracting causing variations in income and demanding greater rationalization at the level of expenditures. For SMEs is essential prepared income and disbursements estimates. Based on the methodology proposed, predictions are made to achieve the objectives of SMEs. Directors will be able to make more successful decisions for the benefit of their companies, to streamline operations, direct the achievement of objectives, rationalize expenses (costs and expenses), and to project better scenarios in the future before carrying out cost-benefit analysis.