You have to make the array constant a vertical array. Using commas makes it
a horizontal array. Replace the commas with semicolons:

=SUMPRODUCT(--(A10:U10={"P";"B";"S";"V";"H";"PBSVH"}))

--
Biff
Microsoft Excel MVP


"PFB" wrote in message
...
The following formula works on a column range (A1:A40), but not on a row
range (A10:U10). What have I missd?

=SUMPRODUCT(--(A10:U10={"P","B","S","V","H","PBSVH"}))