=SUMPRODUCT((A1:Z1=DATE(2007,1,3))*(A1:Z1<=DATE(2 007,1,6))*(A2:N2))
Sum's Mar,Apr,May,Jun


"JMSatMetro" skrev:

I have a worksheet with data arranged in columns, where column headers are
months/years.

I want to be able to use user-input "begin" and "end" dates, and allow
columns in a specified row to be summed, which match these dates.

How to accomplish this?