I will run another calculation (slightly different) on the basis of the code provided by you (hopefuly) and the results will go into the new file C2, C3, etc., then I will
just make some basic calculations between columns B and C directly in the new file.
What will you do with the old file with all the formulas up to N2 inclusive?

As you see from snb's post c00 is the same value as N2, but he never put the CSV file on a spreadsheet.


I am trying to be more clear. With VBA, we can use the CSV file to compute the value you want in B2, B3, etc. We (may be,) can do the same with the value you want in C2, C3, etc. D2, D3, etc, E2, E3. Etc, etc etc. This is much faster

Do you must also have 50k Excel files with all the numbers from all the 50K CSV files? Saving and keeping the old excel file is slower. If you must keep the numbers, is it OK to keep them all on one worksheet?