Technically a student only needs room to stretch their arms and spin around. On that basis we could fit perhaps 60 children in a session. A better question is, what is your instructor to student ratio? This will depend greatly on many different factors including the seasonal variations. However, to give you some idea it is rare to see an OSMA instructor teaching unassisted. Large classes can create a fantastic atmosphere, but still need to be staffed appropriately. The larger the class and more importantly, the greater the ability spread, the more assistants we bring in.  Where appropriate, classes are divided into ability groups and allotted an individual tutor for that section of the class. As a very general guide, you child is likely to experience a staff to pupil ratio of 1:8. It is very common for a student who is struggling with an element of the syllabus, to be given 1 to 1 tuition until they have progressed sufficiently.