This study describes a practical and scalable preliminary method for optimizing paediatric chest X-ray examinations. The study was carried out in a large private healthcare network containing digital radiography and computed radiography systems from multiple vendors. The aim was to achieve a harmonized dose optimization strategy consistent with the national diagnostic reference level and achievable dose level curves established by the Finnish Radiation and Nuclear Safety Authority in paediatric chest X-ray examinations. By using a reference device and calculating conversion factors for mAs normalization, similar or almost similar optimized exposure values could be applied to a wide range of systems. The method was proven to be effective, demonstrating its potential for broader implementation. Following this preliminary optimization, device-specific optimization should continue, particularly for equipment representing newer technology that enables further dose reduction.