Trying to calculate monthly instalments into weekly instalments but realise that some months have 4 weeks and others have 5?
The best way to calculate instalments according to payment frequency is to first arrive at an annual price,
E.G $100 a month is $1,200 a year
The weekly price for the same membership is $1,200 / 52 weeks = $23.08 per week.
That methodology ensures that a client always pays the same amount, over the same period, for the same membership, irrespective of the frequency that they opt to pay.