Macro To Fill Down Formula As Many As There Is Data

Let's say I have data from column A up to column J.

Columns M, N, O contain formulas which calculate value from column J. Since this sheet is a template, the number of rows of data vary from month to month, i.e. the amount of records I copy and paste to columns A-J vary.

I would like to have a macro which will fill down the formulas in columns M, N and O as many as there is data in column J. Example: Let's say minimum number of row is 100, so up to row 100, column J already contains formulas. But if the following month the number of rows is 150, I would like the macro to automatically fill down the formulas in columns M, N and O up to row 150. But if the following month, there is only 130 rows, the macro should fill down to row 130 only.