I'm obviously doing something wrong as it still doesn't work.
All data on one workhseet. Dates to be searched are in column K.
Dates from and to are in two seperate cells in different columns.
using the following formula
=SUMPRODUCT(--(K2:K500<=DD401), --(K2:K500>=DE401)) - typed exactly as shown
produces the result 0 but there is data that should have been counted. Any
further advice?