Change the naming convention of the variables to reflect a Double data type (e.g. Private _dblLength As Double). Public Class frmFence Private Sub totalBtn_Click(sender As Object, e As EventArgs) Handles btnTotal.Click Dim len As Double = 0 Dim wid As Double = 0 Dim lCost As Double = 0 Dim perimeter As Double = 0 Double.TryParse(txtLength.Text, len) Double.TryParse(txtWidth.Text, wid) Double.TryParse(txtLCost.Text, lCost) 'Dim houseArea As My.Resources.Rectangle = New My.Resources.Rectangle() Dim house As Rectangle = New Rectangle(len, wid) perimeter = house.GetPerimeter() lblTotalCost.Text = (perimeter * lCost).ToString("C2") End Sub Private Sub exitBtn_Click(sender As Object, e As EventArgs) Handles btnExit.Click Me.Close() End Sub End Class