Sum the numbers in the filtered list:

After filtering the rows in a list, you can use the SUBTOTAL function, instead of the Excel SUM function, to sum the numbers in the visible rows.
A SUBTOTAL formula will be automatically inserted, while clicking the AutoSum button to total the visible cells in the column or manually keying the formula =SUBTOTAL(109,B2:B9)
The first argument in the SUBTOTAL function is a function number that specifies how the numbers should be calculated. There is a 9 in this example, which tells Excel to SUM the numbers.
Other function numbers can be used, such as 1 for AVERAGE, and 3 for COUNTA. Look in Excel's Help for a complete list.