If by "tab" you mean cell (since the worksheet tabs containing the
worksheet names at the bottom of the window cannot be blank), one way:

=IF(A2="PSS",A1*70%,IF(A2="Derma",A1*80%,""))


In article ,
Caroline wrote:

how do I create a function where if this tab says PSS then you need to
calculate A1 * 70% and if the tab instead says Derma then it should be A1 *
80% if it tab is blank, don't calculate anthing.