my question, it concerns an invoice: if a field is not empty (vat = 6%), a second field (the amount of the vat: price x 6%) has a calculation.

If the field of the vat is empty, the second field must be empty, not '0' but really empty.

Please help how the script must be.

calc_amt = If ( IsEmpty(vat) ; "" ; price*vat/100 )

how you have your vat (6 ≠ .06) may determine if you need to divide by 100.

The IsEmpty() is the test. The "" is not 0.

Beverly