The purpose of this prospective single center study is to investigate if the accuracy of length based body weight estimation by the already investigated algorithm (CLAWAR) can be improved by adding another parameter. For this study 500 patients are required to collect anonymized data (length, weight, age, mid upperarm circumference and patient habitus by visual estimation) for achieving a power of 80% during statistical analysis. The main hypothesis ist that CLAWAR's accuracy can be improved.