Hi Stuart,

I've left the macro method alone while you have a look at the formula options that John and myself have provided.

I haven't looked at the new sample yet, but looking if the file size is anything to go by, I think that the formulas will take a lot of processing.

I'll have a look at the formulas to see if I can find a way to make them run more efficiently, but I don't think that there will be any way to eliminate the countif part of my first formula, which I think will be one of the bigger burdens on processing.