I have been trying to find information about rates currently charged in the marketplace. I have been able to determine what is typically charged for one to one lessons. The range for what is commonly charged appears to be 2,500 yen to 5,000 yen per hour. Of course, some teachers charge less, and some charge more than the rates in that range. So far, I have not found much information about group rates. I know many teachers use a sliding scale system: the greater the number of students in a lesson, the less each student pays. However, I am not sure how much I should reduce the one to one rate for each student who wants to take lessons in a pair or group. For example, if the one to one rate is 4,000 yen per hour, what would be an appropriate rate for each student studying in a pair, in a group of three, in a group of four, and so on?
I was wondering if anyone could provide or direct me to guidelines related to calculating rates for pairs or groups using a sliding scale system.