Fortunately, there’s an easy fix that allows the form designer to configure the calculation order correctly by moving calculated fields up or down to correct the order.
I have responded to a lot of inquiries from form designers over the years about about why simple math calculations in their PDF fillable forms don’t seem to work. They will say things like:
“I tripled-checked my calculations and they are correct, but the form is not calculating properly.”
Or
“It’s calculating correctly, but only after I change another field value. It always seems to be one step behind. I’m so frustrated.”
Frustrated indeed. The good news is, that frustration quickly evaporated once they applied the simple fix of which they were previous unaware.



