Suppose A1 = 11/06 (Date formatted as mm/yy), Sales data is on a tab called
SalesOrders with the dates in A1:A100 and sales in B1:B100:

Try:
=SUMPRODUCT(--(MONTH(SalesOrders!A1:A100)=MONTH(B1)),
--(YEAR(SalesOrders!A1:A100)=YEAR(B1)), SalesOrders!B1:B100)


"Secret Squirrel" wrote:

I have a worksheet (sales orders) that has a list of sales orders that I need
to total up on a different summary worksheet by month. On the sales order
worksheet I have one column that has the sales order date and another that
has the total price. What I want to do is have all the sales added up for
each month on another worksheet. The headers I have on the summary worksheet
are "11/06", "12/06", etc. I want it to just put the summary for each month
it finds on the sales order worksheet under the correct month.