Hi Greg

You were getting errors in the userform initialise module because you were trying to sum the whole of columns L and N. L1 and N1 contain text which caused it to throw errors. I've changed the ranges to go from row 3 to the last used row of those columns.
The userform shows when the button is pressed, but doesn't do anything.

With the worksheet change code it appears you want to check the dropdowns in column C for the word Mileage. I changed the code to do that & for demo purposes, put the formula in column O. It's probably not the final product but should hopefully set you in the right direction. I didn't know what all the original code was for, but it did look a bit over complicated for such a simple task. Or have I got it wrong lol

Cheers
Phil

Attached Files

Mileage(1) .xlsm (34.1 KB, 11 views)