Need formula to calculate unemployment insurance costs.

I am trying to find a formula that will calculate the unemployment insurance costs by employee by month. Our current rate is 0.0158 and is only charged for the first $7000 per employee.

Are you trying to say that they are only charged 1.58% until they reach $7000, in which they are then not charged anymore? I'm confused.

Yes, you are correct.

Assuming that the value is in cell A1:
=IF(A1*0.0158>=7000,7000,A1*0.0158)