Thank you for the suggestions folks. I'm not sure how to go about the If method and I'm not very good with creating Macros from scratch (the one in the workbook took hours and a lot of Google time)

The problem with having a data tab is that the document is dynamic i.e. project details will be reviewed on a regular basis and re-forecast, with projects coming on and dropping off (it would help if the company would invest in a system that was capable of doing all of this!).

But also, the budget template may represent the cost of one day. Then in the Total Cost tab, the number of days is phased in columns J to U. So the data tab would have to consolidate the details from the budget template several times (i.e. once for each day).

I wouldn't know where to begin with a Macro like that