A defined daily dose for children (cDDD) taking body weight into account, was proposed as a better measure of drug utilization in children than the World Health Organization's DDD. There is no global definition of DDDs for children, and it is unclear which standard doses should be used for children when conducting drug utilization studies. We used doses according to the authorized medical product information and body weight according to national pediatric growth curves to calculate theoretical cDDD for three common medicines in children in a Swedish setting. These examples demonstrate that the concept of cDDD may not be optimal for drug utilization studies in children, especially not for younger children and when dosing is done according to weight is crucial. Validation of cDDD in real-world data is warranted. When conducting pediatric drug utilization studies, accessibility to individual-level data on body weight and age combined with dosing information is needed.