The main purpose of this research is to determine the tread sizes that best provide physical comfort by examining user satisfaction. Furthermore, this ergonomic design-oriented study also strives to contribute to the development and improvement of stair standards employed in various countries. In accordance with this goal, an experimental platform was formed and different anthropometric dimensions affecting users' physical comfort level were measured. This study was conducted with 400 volunteers and healthy people between the ages of 18 and 40, and a survey was applied that investigated the prototype stair model on which different tread forms could be experienced and preferences for tread size determined. As a result, a theoretical basis for the factors affecting user satisfaction on stairs was formed and tread sizes considering people's anthropometric dimensions were suggested. As distinct from former studies, one of the prominent findings here concerns the range of leg angle corresponding to the size requirements of the stairs. The physical comfort range is determined by questioning user satisfaction through the mentioned angle relation.