Is it possible that rows are inserted in the Monday sheet at the top? If 9 rows were inserted, for instance, then the formula in Summary sheet would change to ths

=SUM(IF(Monday!$B$10:$B$50

i.e. all ranges are pushed down by 9 rows.

If rows are to be added to Monday sheet then they should be added

**below row 1**- that will still extend the ranges in your formulas....but they'll still start at row 1 so all the data will be covered

You could perhaps consider using dynamic named ranges in the Monday worksheet. If you define a named range MonA based on the number of entries in that column (with COUNTA), i.e. using this formula

=INDEX(Monday!$A:$A,1):IND

and also apply named ranges to columns B and E in the same way then your formula can be reduced to this non-array version

=SUMPRODUCT((MonB=$B8)*(Mo

See attached example

Try adding another entry in Monday with "x" in A51, "y" in B51 and any number in E51 - notice that this amount will automatically be added to the total in C9

Note that the named ranges only work if one column in Mondays sheet will have continuous values from row 1 - then the named ranges for all columns can be based on that one - I used column A for that purpose

regards, barry