If you are rounding just because you want to limit the numbers displayed after decimal point, you can also use the Format function to do that, and still retain the multiple decimals for accuracy in other calcs.

Eg.
Code:
answer = WeightInKg / ((HeightInCm /100)^2)
MsgBox("BMI: " & Format(answer, "#,##0.00") & " kg/m2", MsgBoxStyle.OkOnly, "BMI Result")